TON MODELS 50 HERTZ STYLE D

Transcription

1 Millennium TM AIR COOLED SCREW LIQUID CHILLERS AIR COOLED SCREW HERMETIC INSTALLATION, OPERATION, MAINT. Supersedes: Nothing FORM NM2 (696) TON MODELS 50 HERTZ STYLE D #27960 With EPROM (Standard, Brine & Metric Models, Combined)

2 TABLE OF CONTENTS GENERAL CHILLER INFORMATION NOMENCLATURE OPERATIONAL LIMITATIONS PHYSICAL DATA DIMENSIONS ELECTRICAL DATA CHILLER COMPONENTS COMPRESSOR COMPONENTS GENERAL INSTALLATION WIRING DIAGRAM UNIT CONTROLS AND OPERATION SAFETIES GENERAL CHILLER INFORMATION The Millennium Air Cooled Screw liquid chiller is completely assembled with all interconnecting refrigerant piping and internal wiring, ready for field installation. The unit is pressure-tested, evacuated, and fully charged with Refrigerant-22, and includes an initial oil charge. After assembly, an operational test is performed with water flowing through the cooler to check that each refrigeration circuit operates correctly. The unit structure is heavy gauge, galvanized steel, covered with a baked-on enamel. Base rails are of formed double thickness, painted plate steel. Units are designed in accordance with ARI 550, NFPA 70 (National Electrical Code), ASHRAE/ANSI 15 Safety code for mechanical refrigeration and ASME. Units are rated in accordance with ARI Standard YORK INTERNATIONAL

3 UNIT NOMENCLATURE FORM NM2 The model number denotes the following characteristics of the unit: YE A S Y D YORK Chiller Design Series Air Cooled Compressor Design Series S = Screw Unit Model Type Start Y = WYE-Delta X = Across-the-Line Voltage Code: 50 = 380/ YORK INTERNATIONAL 3

4 Engineering Data (stamped on unit nameplate) denotes the following characteristics of the components of the unit: 4 M 2 A 3 H L 6 A 2 Compressor "W" Chiller Configuration containing 4 Fans & 8 Coils per Module 1 = 50 Hz, Economized, 1 Module 2 = 60 Hz, Economized, 1 Module 3 = 50 Hz, Economized, 1.5 Module 4 = 60 Hz, Economized, 1.5 Module 5 = 50 Hz, Economized, 2 Module 6 = 60 Hz, Economized, 2 Module 7 = 50 Hz, Economized, 2.5 Module 8 = 60 Hz, Economized, 2.5 Module Gear in System #1 XHS120 Compressor (A, M, F, H, P or S) Motor in System #1 Compressor 50 Hz Max. KW 0 = 101 Frame, 7" Long 61 1 = 101 Frame, 8" Long 72 2 = 101 Frame, 9" Long 90 3 = 101 Frame, 9.5" Long 98 4 = 101 Frame, 10" Long N/A 5 = 101 Frame, 10.75" Long = 124 Frame, 9.5" Long (G) = 124 Frame, 9.5" Long (K) = 124 Frame, 10.75" Long (P) N/A 9 = 124 Frame, 10.75" Long(M) 213 Cooler Code H = 16" Cooler K = 18" Cooler N = 20" Cooler Motor in System #2 Compressor (See System #1 motor list) Refrigerant Code A = R-22 B = R-134a Condenser Fan Code 6 or 7 Condenser Code L = 32" x 83" 3 row deep coils in both systems M = 32" x 83" 4 row deep coils in System #1 3 row deep coils in System #2 N = 32" x 83" 4 row deep coils in both systems Gear in System #2 XHS120 Compressor (A, M, F, H, P or S) 4 YORK INTERNATIONAL

5 FORM NM2 OPERATIONAL LIMITATIONS VOLTAGE LIMITATIONS The following voltage limitations are absolute and operation beyond these limitations may cause serious damage to the compressor. VOLTAGES DX COOLER P - FT. H 2 O GPM UNIT POWER MIN. MAX. 380/ TEMPERATURES AND FLOWS MODEL YEAS LEAVING WATER TEMPERATURE F COOLER GPM. AIR ON CONDENSER F MIN. 1 MAX. MIN. MAX. MIN. MAX FIG. 1 - COOLER WATER PRESSURE DROP FOR ALL MODELS NOTES: 1. Units can be used for brine temperatures down to 35 F by resetting standard controls. For leaving brine temperatures down to 15 F, contact your nearest YORK office. 2. Operation above 115 F requires the optional High Ambient Kit. Contact your nearest YORK office. YORK INTERNATIONAL 5

6 PHYSICAL DATA MODEL YEAS NOMINAL TONS NO. OF REFRIG CIRCUITS COMPRESSOR MODEL XHS SYS 1 120BA*G 120BM*L 120BF*L 120BF*L 120CH*N 120CP*N 120CP*Q 120CS*Q 120CP*Q SYS 2 120BA*G 120BM*G 120BM*L 120BF*L 120CH*N 120BH*L 120CP*N 120CS*Q 120CP*Q COOLER DIAMETER X LENGTH 16" x 8 16" x 8 16" x 8 18" x 8 18" x 8 18" x 8 18" x 8 18" x 8 18" x 8 VOLUME (GAL.) GPM CONDENSER ROWS MIN MAX SYS SYS FACE AREA SQ. FT CONDENSER FANS NO HP/KW 3/2.3 3/2.3 3/2.3 3/2.3 3/2.3 3/2.3 3/2.3 3/2.3 3/2.3 NO. OF BLADES CFM 135, , , , , , , , ,000 WEIGHT (LBS.) SHIPPING OPERATING REFRIGERENT CHARGE (LBS. R-22) Al. FIN 14,132 14,132 14,132 14,932 14,932 14,932 14,932 14,932 14,932 Cu. FIN 16,408 16,408 16,408 17,208 17,208 17,208 17,208 17,208 17,208 Al. FIN 14,522 14,522 14,522 15,322 15,322 15,322 15,322 15,322 15,322 Cu. FIN 16,798 16,798 16,798 17,598 17,598 17,598 17,598 17,598 17,598 SYS SYS * = Voltage Code 6 YORK INTERNATIONAL

7 DIMENSIONS FORM NM2 NOTES: 1. Clearances - Minimum YORK required clearances to prevent condenser air recirculation and faulty operation of units are as follows: Side to wall 8 0"*; Rear to wall 8 0"; Control Panel End to wall 5 0"*; Distance between adjacent units 12 0" *No more than one wall can be higher than the top of the unit. The area within the clearances shown above and area under the unit must be kept clear of all obstructions that would impede free air flow to the unit. In installations where winter operation is intended and snow accumulations are expected, additional unit height must be provided to insure full air flow. NOTE: Reduced clearances may be used due to jobsite restrictions. The unit will automatically unload as required (discharge pressure unloading and motor current unloading) to prevent condenser pressure from exceeding the High Pressure Cut-out or High Current Cut-out. This will result in capacity reduction. 2. Cooler liquid connection sizes (inlet and outlet) 8" victaulic for all models. 3. Dimensions are in inches. 4. Spring isolators (OPTIONAL) will increase overall height of unit. Refer to page 30 and 31 for details. 5. Modules have 1-1/8" of space between to facilitate maintenance. YORK INTERNATIONAL 7

8 ELECTRICAL DATA STANDARD DUAL-POINT POWER SUPPLIES (Each power supply individually field-supplied with branch circuit protection) MODEL VOLTS MCA 1 SYSTEM #1 FIELD-SUPPLIED WIRING MIN NF D.E. FU 3 C.B. 4 WIRE RANGE COMPRESSOR FANS DISC SW 2 MIN. MAX. MIN. MAX. WYE-DELTA 5 ACR-LINE 5 RLA YLRA XLRA FLA(ea) YEAS (2) #8-1/0 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A NOTES: 1. Minimum Circuit Ampacity (MCA) is based on 125% of the rated load amps (RLA) for the largest motor plus 100% of the RLAs for all other loads included in the circuit, per N.E.C. Article If a factory-mounted control transformer is provided, add 3 amps to the System #1 MCA values. 2. Minimum Non-Fused Disconnect Switch size is based on a minimum of 115% of the sum of the RLAs for all the loads included in the circuit, per N.E.C A1. 3. Minimum Dual Element Fuse size is based on 150% of the largest motor RLA plus 100% of the remaining RLAs. (U.L. Standard 1995, Section 36.1). It is not recommended in applications where brown-outs, frequent starting and stopping of the unit, and/or operation at ambient temperatures in excess of 95 F is anticipated. Maximum Dual Element Fuse size is based on 225% maximum RLA plus 100% of the RLAs for all other loads included in the circuit, per N.E.C Minimum fuse rating = 1.5 x Compr RLA + 4 x Fan FLA. Maximum fuse rating = 2.25 x Compr RLA + 4 x Fan FLA (each compressor system). 4. Minimum and maximum Circuit Breaker rating required per N.E.C. Minimum C.B. rating = 1.5 x Compr RLA + 4 x Fan FLA. Maximum C.B. rating = 2.25 x Compr RLA + 4 x Fan FLA (each compressor system). 5. Wire Range is the minimum and maximum wire size that can be accommodated by the unit wiring lugs. The (1), (2) or (3) preceding the wire range indicates the number of termination points available per phase. The (1-2) preceding the wire range indicates that a single double-barreled lug is available per phase that can accept up to two wires of the wire range specified. "(1) #1-600 or (2) #1-250" indicates that a single lug is supplied and it will accept a single wire up to 600MCM or 2 wires up to 250MCM. Actual wire size and number of wires per phase must be determined based on ampacity and job requirements using N.E.C. wire sizing information. The above recommendations are based on the National Electrical Code and using copper connectors only. Field wiring must also comply with local codes. 8 YORK INTERNATIONAL

9 FORM NM2 STANDARD DUAL-POWER SUPPLIES (Each power supply individually field-supplied with branch circuit protection) MODEL VOLTS MCA 1 SYSTEM #2 FIELD-SUPPLIED WIRING MIN NF D.E. FU 3 C.B. 4 WIRE RANGE COMPRESSOR FANS DISC SW 2 MIN. MAX. MIN. MAX. WYE-DELTA 5 ACR-LINE 5 RLA YLRA XLRA FLA(ea) YEAS (2) #8-1/0 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A YEAS (2) #6-250 N/A LEGEND ACR-LINE C.B. D.E. FU DISC SW FLA HZ MAX. MCA MIN. MIN NF RLA WYE-DELTA XLRA YLRA ACROSS THE LINE START CIRCUIT BREAKER DUAL ELEMENT FUSE DISCONNECT SWITCH FULL LOAD AMPS HERTZ MAXIMUM MINIMUM CIRCUIT AMPACITY MINIMUM MINIMUM NON-FUSED RATED LOAD AMPS WYE-DELTA START ACROSS-THE-LINE LOCKED ROTOR AMPS WYE-DELTA, Y LOCKED ROTOR AMPS YORK INTERNATIONAL 9

10 OPTIONAL SINGLE-POINT POWER SUPPLY MODEL VOLTS MCA 1 2, 3, 4, 6 FIELD-SUPPLIED WIRING MIN NF D.E. FU 3 C.B. 4 DISC SW 2 WIRE RANGE 5 MIN. MAX. MIN. MAX. YEAS (1) #1-600 or (2) #1-250 YEAS (1) #1-600 or (2) #1-250 YEAS (3) 3/0-500 YEAS (3) 3/0-500 YEAS (3) 3/0-500 YEAS (3) 3/0-500 YEAS (3) 3/0-500 YEAS (3) 3/0-500 YEAS (3) 3/0-500 NOTES: 1. Minimum Circuit Ampacity (MCA) is based on 125% of the rated load amps (RLA) for the largest motor plus 100% of the RLAs for all other loads included in the circuit, per N.E.C. Article If a factory-mounted control transformer is provided, add 3 amps to the MCA values. 2. Minimum Non-Fused Disconnect Switch size is based on a minimum of 115% of the sum of the RLAs for all the loads included in the circuit, per N.E.C A1. Available as factory-mounted option on units with single-point power supply. 3. Minimum Dual Element Fuse size is based on 150% of the largest motor RLA plus 100% of the remaining RLAs. (U.L. Standard 1995, Section 36.1). It is not recommended in applications where brown-outs, frequent starting and stopping of the unit, and/or operation at ambient temperatures in excess of 95 F is anticipated. Maximum Dual Element Fuse size is based on 225% of the maximum RLA plus 100% of the RLAs for all other loads included in the circuit, per N.E.C Minimum fuse rating = 1.5 x Largest Compr RLA + Other Compr RLA + 8 x Fan FLA. Maximum fuse rating = 2.25 x Largest Compr RLA + Other Compr RLA + 8 x Fan FLA. These sizes are for field-supplied fuses. For factory-mounted fuses, see sizes on the next page. 4. Minimum and maximum Circuit Breaker rating required per N.E.C. Minimum C.B. rating = 1.5 x Largest Compr RLA + Other Compr RLA + 8 x Fan FLA. Maximum C.B. rating = 2.25 x Largest Compr RLA + Other Compr RLA + 8 x Fan FLA. Available as factory-mounted option on units with single-point power supply. 5. Wire Range is the minimum and maximum wire size that can be accommodated by the unit wiring lugs. The (1), (2), or (3) preceding the wire range indicates the number of termination points available per phase. The (1-2) preceding the wire range indicates that a single double-barreled lug is available per phase that can accept up to two wires of the wire range specified. "(1) #1-600 or (2) #1-250" indicates that a single lug is supplied and it will accept a single wire up to 600MCM or 2 wires up to 250MCM. Actual wire size and number of wires per phase must be determined based on ampacity and job requirements using N.E.C. wire sizing information. The above recommendations are based on the National Electrical Code and using copper connectors only. Field wiring must also comply with local codes. 6. When fuses are factory-mounted, this is the minimum and maximum Dual Element Fuse rating required per N.E.C. Minimum fuse rating = 1.5 x Compr RLA + 4 x Fan FLA. Maximum fuse rating = 2.25 x Compr RLA + 4 x Fan FLA (each compressor system). Available as factory-mounted option on units with single-point power supply and factory-mounted non-fused disconnect switch. 10 YORK INTERNATIONAL

11 FORM NM2 OPTIONAL SINGLE-POINT POWER SUPPLY MODEL FACTORY-MOUNTED FUSE SYSTEM #1 SYSTEM #2 COMPRESSOR FANS FACTORY-MOUNTED FUSE COMPRESSOR MIN. 6 MAX. 6 RLA YRLA XLRA FLA(ea) MIN. 6 MAX. 6 RLA YLRA XLRA FLA(ea) YEAS YEAS YEAS YEAS YEAS YEAS YEAS YEAS YEAS FANS LEGEND ACR-LINE C.B. D.E. FU DISC SW FLA HZ MAX. MCA MIN. MIN NF RLA WYE-DELTA XLRA YLRA ACROSS THE LINE START CIRCUIT BREAKER DUAL ELEMENT FUSE DISCONNECT SWITCH FULL LOAD AMPS HERTZ MAXIMUM MINIMUM CIRCUIT AMPACITY MINIMUM MINIMUM NON-FUSED RATED LOAD AMPS WYE-DELTA START ACROSS-THE-LINE LOCKED ROTOR AMPS WYE-DELTA, Y LOCKED ROTOR AMPS YORK INTERNATIONAL 11

12 OPTIONAL SINGLE-POINT POWER SUPPLY WITH SEPARATE CIRCUIT BREAKERS FOR EACH REFRIGERANT SYSTEM MODEL VOLTS MCA 1 FIELD-SUPPLIED WIRING 4, 6 MIN NF D.E. FU 3 C.B. 4 DISC SW 2 WIRE RANGE 5 MIN. MAX. MIN. MAX. YEAS (1) #1-600 or (2) #1-250 YEAS (1) #1-600 or (2) #1-250 YEAS (1) #1-600 or (2) #1-250 YEAS (1) #1-600 or (2) #1-250 YEAS (1) #1-600 or (2) #1-250 YEAS (3) 3/0-500 YEAS (3) 3/0-500 YEAS (3) 3/0-500 YEAS (3) 3/0-500 NOTES: 1. Minimum Circuit Ampacity (MCA) is based on 125% of the rated load amps (RLA) for the largest motor plus 100% of the loaded RLAs for all other loads included in the circuit, per N.E.C. Article If a factory-mounted control transformer is provided, add 3 amps to the MCA values. 2. Minimum Non-Fused Disconnect Switch size is based on a minimum of 115% of the sum of the RLAs for all the loads included in the circuit, per N.E.C A1. 3. Minimum Dual Element Fuse size is based on 150% of the largest motor RLA plus 100% of the remaining RLAs. (U.L. Standard 1995, Section 36.1). It is not recommended in applications where brown-outs, frequent starting and stopping of the unit, and/or operation at ambient temperatures in excess of 95 F is anticipated. Maximum Dual Element Fuse size is based on 225% of the maximum RLA plus 100% of the RLAs for all other loads included in the circuit, per N.E.C Minimum fuse rating = 1.5 x Largest Compr RLA + Other Compr RLA + 8 x Fan FLA. Maximum fuse rating = 2.25 x Largest Compr RLA + Other Compr RLA + 8 x Fan FLA. 4. Minimum and maximum Circuit Breaker rating required per N.E.C. Mininimum C.B. rating = 1.5 x Largest Compr RLA + Other Compr RLA + 8 x Fan FLA. Maximum C.B. rating = 2.25 x Largest Compr RLA + Other Compr RLA + 8 x Fan FLA. These sizes are for field-supplied circuit breakers. For factory-mounted circuit breakers, see sizes on the next page. 5. Wire Range is the minimum and maximum wire size that can be accommodated by the unit wiring lugs. The (1), (2), or (3) preceding the wire range indicates the number of termination points available per phase. The (1-2) preceding the wire range indicates that a single double-barreled lug is available per phase that can accept up to two wires of the wire range specified. "(1) #1-600 or (2) #1-250" indicates that a single lug is supplied and it will accept a single wire up to 600MCM or 2 wires up to 250MCM. Actual wire size and number of wires per phase must be determined based on ampacity and job requirements using N.E.C. wire sizing information. The above recommendations are based on the National Electrical Code and using copper connectors only. Field wiring must also comply with local codes. 6. When circuit breakers are factory-mounted, this is the minimum and maximum circuit breaker rating required per N.E.C. Minimum C.B. rating = 1.5 x Compr RLA + 4 x Fan FLA. Maximum C.B. rating = 2.25 x Compr RLA + 4 x Fan FLA (each compressor system). Available as factory-mounted option on units with single-point power supply. 12 YORK INTERNATIONAL

13 FORM NM2 OPTIONAL SINGLE-POINT POWER SUPPLY WITH SEPARATE CIRCUIT BREAKERS FOR EACH REFRIGERANT SYSTEM MODEL VOLTS FACTORY-MOUNTED C.B. SYSTEM #1 SYSTEM #2 COMPRESSOR FANS FACTORY-MOUNTED C.B. COMPRESSOR FANS MIN. 6 MAX. 6 RLA YRLA XLRA FLA(ea) MIN. 6 MAX. 6 RLA YRLA XLRA FLA(ea) YEAS YEAS YEAS YEAS YEAS YEAS YEAS YEAS YEAS LEGEND ACR-LINE C.B. D.E. FU DISC SW FLA HZ MAX. MCA MIN. MIN NF RLA WYE-DELTA XLRA YLRA ACROSS THE LINE START CIRCUIT BREAKER DUAL ELEMENT FUSE DISCONNECT SWITCH FULL LOAD AMPS HERTZ MAXIMUM MINIMUM CIRCUIT AMPACITY MINIMUM MINIMUM NON-FUSED RATED LOAD AMPS WYE-DELTA START ACROSS-THE-LINE LOCKED ROTOR AMPS WYE-DELTA, Y LOCKED ROTOR AMPS YORK INTERNATIONAL 13

14 CHILLER COMPONENTS POWER PANEL MICRO PANEL COMPRESSOR #1 COMPRESSOR #2 FILTER DRIER LIQUID STOP VALVE FAN ORIFICE CONDENSER COIL FILTER DRIER OUTLET EVAPORATOR INLET ECONOMIZER #27960 #27961 EVAPORATOR HEATER TXV S LIQUID LINE SOLENOID VALVES FILTER DRIER 14 YORK INTERNATIONAL

15 FORM NM2 LEAVING WATER TEMPERATURE SENSOR RETURN WATER TEMPERATURE SENSOR EVAPORATOR OUTLET EVAPORATOR INLET SYS 1 TXV SYS 1 SIGHT GLASS SYS 2 TXV SYS 1 LIQUID LINE SOLENOID VALVE SYS 2 SIGHT GLASS SYS 2 LIQUID LINE SOLENOID VALVE #27967 #27968 YORK INTERNATIONAL 15

16 SLIDE VALVE CONTROL SOLENOID ECONOMIZER PIPING OIL PRESSURE TRANSDUCER OIL INJECTION PIPING MOTOR TERMINAL BOX ECONOMIZER SERVICE VALVE LIQUID STOP VALVE FILTER DRIER #27973 # YORK INTERNATIONAL

17 FORM NM2 OIL LINE SOLENOID VALVE OIL FILTER OIL INJECTION PIPING OIL INJECTION PIPING BALL VALVE (FOR OIL FILTER ISOLATION) FILTER DRIER OIL SEPARATOR RELEF VALVE (NOTE: THIS WILL EVENTUALLY BE BUILT INTO THE OIL SEPARATOR) OIL PRESSURE TRANSDUCER ECONOMIZER ECONOMIZER SOLENOID VALVE ECONOMIZER TXV OIL SEPARATOR OIL SIGHT GLASS OIL CHARGING VALVE #27970 YORK INTERNATIONAL 17

18 SLIDE VALVE CONTROL SOLENOID SUCTION SERVICE VALVE DISCHARGE SERVICE VALVE EVAPORATOR MOTOR TERMINAL BOX SUCTION PRESSURE TRANSDUCER DISCHARGE PRESSURE TRANSDUCER LIQUID INJECTION PIPING LIQUID INJECTION SOLENOID VALVE # YORK INTERNATIONAL

19 FORM NM2 SUCTION SERVICE VALVE DISCHARGE TEMPERATURE SENSOR OIL INJECTION PIPING DISCHARGE PRESSURE TRANSDUCER DISCHARGE SERVICE VALVE LIQUID INJECTION SOLENOID VALVE OIL HEATER ELECTRICAL JUNCTION BOX SLIDE VALVE PISTON OIL SUPPLY / VENT LINE #27970 #27969 YORK INTERNATIONAL 19

20 COMPRESSOR COMPONENTS 20 YORK INTERNATIONAL

21 FORM NM2 * NOTE: * On newer production chillers, this valve will not be located on the compressor. YORK INTERNATIONAL 21

22 FIG. 2 - COMPRESSOR GAS FLOW 22 YORK INTERNATIONAL

23 FORM NM2 FIG. 3 - SCREW CHILLER REFRIGERANT FLOW DIAGRAM YORK INTERNATIONAL 23

24 GENERAL DESCRIPTION The Air Cooled Screw Chiller utilizes many components which are the same or nearly the same as a standard reciprocating chiller of a similar size. This includes modular frame rails, condenser, fans and evaporator. The chiller consists of two screw compressors in two separate refrigerant circuits, a single shell and tube DX evaporator, economizers, an air cooled condenser, and expansion valves. COMPRESSOR The Frick semi-hermetic rotary twin-screw compressor utilizes a twin screw design with a single slide valve for capacity control. The compressor is a positive displacement type characterized by two helically grooved rotors. The 60 Hz motor operating at 2950 RPM drives a geared speed increaser to drive the male rotor between RPM. The female rotor is driven by the male rotor on a light film of oil. Compressors with gear sets running at higher speeds will have greater capacity. Refrigerant gas is injected into the void created by the un-meshing of the 5 lobed male and 7 lobed female rotor. Further meshing of the rotors closes the rotor threads to the suction port and progressively compresses the gas in an axial direction toward the discharge port. The gas is compressed in volume and GENERAL increased in pressure before exiting at a designed volume at the discharge end of the rotor casing. Since the intake and discharge cycles overlap, a resulting smooth continuous flow of gas is maintained. Contact between the male and female rotor is primarily rolling on a contact band on each of the rotors pitch circle. This results in virtually no rotor wear and increased reliability, a trademark of the screw compressor. The compressor incorporates a complete anti-friction bearing design for reduced power input and increased reliability. Four separated, cylindrical, roller bearings handle radial loads. Angular-contact ball bearings handle axial loads. Together they maintain accurate rotor positioning at all pressure ratios, thereby minimizing leakage and maintaining efficiency. A check valve is installed in the compressor discharge housing to prevent compressor rotor backspin due to system refrigerant pressure gradients during shutdown. Motor cooling is accomplished by injecting intermediate pressure wet vapor into the motor which allows for better efficiency than the traditional use of lower pressure suction gas which requires more energy to raise to discharge pressure. The compressor is lubricated by removing oil from the refrigerant using an external oil separator. The pressurized oil is then piped back to the compressor for lubrication. The compressor design working pressure is 144 PSIG on the suction side and 450 PSIG on the discharge side. Each chiller receives a 300 PSIG low side and 450 PSIG high side factory test. A 500 watt ( ) immersion heater is located in the compressor. The heater is temperature activated to prevent refrigerant condensation. EVAPORATOR The system uses a Shell and Tube type Direct Expansion Evaporator. Each of the two refrigerant circuits consists of 4 passes with the chilled liquid circulating back and forth across the tubes from one end to the other. The design working pressure of the cooler shell on the liquid side is 150 PSIG, and 235 PSIG for the tube (refrigerant side). The cooler is equipped with a heater to provide freeze protection to -20 F. Water connections are grooved to accept victaulic couplings. FIG. 4 - COMPRESSOR ROTORS ACTUAL ROTOR ASSEMBLY CONDENSER The air cooled condenser coils use state-of-the-art louvered fins for heat transfer. Eight fans move air through the coils. Design working pressure of the condenser is 450 PSIG. 24 YORK INTERNATIONAL

25 FORM NM2 ECONOMIZER A plate and frame heat exchanger (Economizer) is installed in the high side of each system for subcooling of the primary refrigerant liquid to the evaporator. This increases the efficiency of the system. The wet vapor to the economizer is supplied by a small 20 ton TXV set for 10 F superheat that flashes off 10-20% of the liquid from the condenser tons are utilized for subcooling liquid refrigerant and 2-3 tons for motor cooling. The wet vapor for motor cooling is at an intermediate pressure between discharge and suction and therefore requires little energy to pump it back through the compressor to condenser pressure. This results in a very small loss to system efficiency. The economizer provides approximately 20 F of additional subcooling (15 in, 35 out) to the liquid refrigerant which flows to the evaporator. The subcooled liquid is then fed to the primary TXV in the system. This additional subcooling results in a significant increase in the efficiency of the system. The design working pressure of the economizer is 450 PSIG. The economizer liquid supply solenoid is activated on start-up coincident with the liquid line solenoid, after pumpdown. OIL SEPARATOR / SYSTEM The external oil separator, with no moving parts and designed for minimum oil carry-over, is mounted in the discharge line of the compressor. The high pressure discharge gas is forced around a 90 degree bend and through centrifugal action, oil is forced to the outside of the separator and captured on wire mesh where it drains to the bottom of the oil separator and into the compressor. The oil (YORK "E" oil), which drains back into the compressor through a replaceable micron oil filter, and oil supply solenoid (energized when the compressor starts), is at high pressure. This high pressure "oil injection" forces the oil into the compressor where it is gravity fed to the gears and bearings for lubrication. After lubricating the gears and bearings, it is injected through orifices on a closed thread near the suction end of the rotors. The oil is automatically injected because of the pressure difference between discharge pressure and the reduced pressure at the suction end of the rotors. This lubricates the rotors as well as provides an oil seal against leakage around the rotors to assure refrigerant compression (volumetric efficiency). The oil also provides cooling by transferring much of the heat of compression from the gas to the oil keeping discharge temperatures down and reducing the chance for oil breakdown. Oil injected into the rotor cage flows into the rotors at a point about 1.2x suction. This assures that a required minimum differential of at least 30 PSID exists between discharge and 1.2x suction, to force oil into rotor case, a minimum 10 PSI differential is all that is required to assure protection of the compressor. Oil pressure is measured as the difference between discharge pressure and the pressure of the oil entering the rotor case. Maximum working pressure of the oil separator is 450 PSIG. A relief valve is installed in the oil separator piping. This will soon be incorporated into the oil separator. Oil level should be above the midpoint of the "lower" oil sight glass when the compressor is running. Oil level should not be above the top of the "upper" sight glass. Oil temperature control is provided through liquid injection activated by the microprocessor, utilizing a discharge temperature sensor, and a solenoid valve. OIL COOLING / LIQUID INJECTION SYSTEM A liquid injection system is utilized to maintain oil temperature and proper oil viscosity. Liquid injection is controlled by the microprocessor on a demand basis to provide stable oil/discharge temperature control. A discharge temperature sensor on the compressor sends an analog signal to the microprocessor to allow the micro to monitor oil temperature. The micro in turn controls a solenoid which injects liquid whenever the discharge temperature rises above 180 F and turns it off when temperature falls to 160 F. In most circumstances, liquid injection will not energize during part load operation. CAPACITY CONTROL The function of the compressor capacity control system is to automatically adjust the pumping capacity of the compressor to satisfy the cooling load to regulate leaving water temperature (LWT) within the programmed Control Range (CR). Capacity control is accomplished by moving a slide valve with a series of load and unload pulses which changes the entrance point of the suction gas entering the rotors. This allows refrigerant gas to be injected at virtually any point on the rotors, keeping in mind that a minimum capacity of 15% load is maintained on a compressor for oil return. The micro also attempts to sequence compressor loading to maximize efficiency and minimize compressor cycling. Movement of the slide valve is accomplished by forcing pressurized oil against a piston which drives the slide valve open to load the compressor. Electrical pulses open a solenoid valve, allowing oil pressure to move the piston which operates the slide valve. The pulses originate at the micro and are a function of the required load on the chiller in response to leaving water temperature. The micro must repetitively pulse the slide valve to maintain a constant load. This is required because YORK INTERNATIONAL 25

26 discharge pressure is always present on the other end of the slide valve, trying to force it closed. To unload the compressor, a second solenoid is opened, which vents oil pressure away from the piston. By releasing the pressure on the piston, the discharge pressure is able to push the valve toward the closed or unload position. It will be noted that slide valve movement is greater at high discharge pressures. This is due to higher oil pressure which is directly proportional to discharge pressure. Higher oil pressures exert more pressure on the slide valve causing greater movement as the slide valve is pulsed with oil. This condition is normal. Also normal and a result of compressor design is non-linear movement at various points in the slide valve travel as the slide valve is pulsed. Closely monitoring the movement will show that the slide valve will move easier at the ends and in the center of its travel range. When the compressor is shut down, a check valve releases oil from the piston. Since no discharge pressure is available to push the valve closed, the slide valve will maintain the position it was in when the compressor stopped. To assure the compressor starts unloaded, the micro sends an unload signal to the slide valve on start-up. In some cases, oil pressure may not be high enough at start-up to move the slide valve. This means the compressor could start-up partially loaded. This will seldom occur and will not hurt the motor due to the extra torque built into the design. STARTER Two types of compressor motor starting are available: Across-the-line and optional Wye-Delta Closed Transition Starter. The Across-the-line starters will utilize one contactor per compressor. The optional Wye-Delta starter utilizes 4 contactors, a time delay relay, and wire wound power resistors for each compressor. See Fig. 5. The Wye-Delta start allows inrush current to be limited to approximately 33% LRA for the first 15 seconds with current increasing to normal running current when the Delta connection is completed. When the micro initiates a start signal to run a compressor, the 1CR (SYS 1) or 2CR (SYS 2) relay is energized. At the same time, the 1TR (SYS 1) or 2TR (SYS 2) "15 second" time delay relay is energized and begins timing. The transition of the 1CR (SYS 1) or 2CR (SYS 2) contactor also energizes 1S (SYS 1) or 2S (SYS 2) normally open auxiliary interlock contacts after approximately 16ms which in turn energizes the 1M (SYS 1) or 3M (SYS 2) motor contactor after approximately another 16ms. This completes the "WYE" connection of the motor start. At the same time, the normally closed 1S or 2S auxiliary interlock open, preventing 2M (SYS 1) or 4M (SYS 2) from energizing. The "WYE" connection of the motor start is enabled for approximately 15 seconds. When the 1TR or 2TR timer times out after 15 seconds, the interlock contacts energize 1A (SYS 1) or 2A (SYS 2) "TRANSITION" contactor which puts the resistance networks across each winding of the "WYE" connection. At the same time, the normally closed 1A or 2A auxiliary interlock contacts de-energize 1S or 2S after approximately 16ms. The normally closed auxiliary interlock contacts on 1S or 2S will close energizing 2M or 4M after approximately 16ms. With the 1M or 3M contactors already held in by the 1M or 3M auxiliary contacts and 2M or 4M energized, the normally closed auxiliary interlock contact on 2M or 4M contactor holding in the 1A or 2A "TRANSITION" contactor opens removing the resistor network and completing the "DELTA" connection of the "WYE-DELTA" start. #27963 FIG. 5 - POWER PANEL (WITH WYE-DELTA STARTING) 26 YORK INTERNATIONAL

27 FORM NM2 INSTALLATION WARNING To protect warranty, this equipment must be installed and serviced by an authorized YORK service mechanic or a qualified service person experienced in chiller installation. Installation must comply with all applicable codes, particularly in regard to electrical wiring and other safety elements such as relief valves, HP cut-out settings, design working pressures, and ventilation requirements consistent with the amount and type of refrigerant charge. Lethal voltages exist within the control panel. Before servicing, open and tag all disconnect switches. INSTALLATION CHECK LIST The following items, 1 thru 5, must be checked before placing the units in operation. 1. Inspect the unit for shipping damage. 2. Rig unit per Fig. 6. Remove unpainted shipping braces. 3. Open the unit only to install water piping system. Do not remove protective covers from water connections until piping is ready for attachment. Check water piping to insure cleanliness. 4. Pipe unit using good piping practice (see ASHRAE handbook section 215 and 195 or YORK Service Manuals for detailed piping). 5. Check to see that the unit is installed and operated within LIMITATIONS. The following pages outline detailed procedures to be followed to install and start up the chiller. HANDLING These units are shipped as completely assembled units containing full operating charge, and care should be taken to avoid damage due to rough handling. The units are shipped with export crating unless it is specified by Sales Order. A unit should be lifted by inserting hooks through the holes provided in unit base rails. Spreader bars should be used to avoid crushing the unit frame rails with the lifting chains. (See Fig. 6.) INSPECTION Immediately upon receiving the unit, it should be inspected for possible damage which may have occurred during transit. If damage is evident, it should be noted in the carrier s freight bill. A written request for inspection by the carrier s agent should be made at once. See instruction NM for more information and details. LOCATION AND CLEARANCES These units are designed for outdoor installations on ground level, rooftop, or beside a building. Location should be selected for minimum sun exposure and to insure adequate supply of fresh air for the condenser. The units must be installed with sufficient clearances for air entrance to the condenser coil, for air discharge away from the condenser, and for servicing access. In installations where winter operation is intended and snow accumulations are expected, additional height must be provided to insure normal condenser air flow. (See DIMENSIONS.) FOUNDATION FIG. 6 - RIGGING THE CHILLER The unit should be mounted on a flat and level foundation, floor, or rooftop capable of supporting the entire operating weight of the equipment. See PHYSICAL DATA for operating weight. If the unit is elevated beyond the normal reach of service personnel, a suitable catwalk must be capable of supporting service personnel, their equipment, and the compressors. YORK INTERNATIONAL 27

28 GROUND LEVEL LOCATIONS It is important that the units be installed on a substantial base that will not settle. A one piece concrete slab with footers extended below the frost line is highly recommended. Additionally, the slab should not be tied to the main building foundations as noise and vibration may be transmitted. Mounting holes are provided in the steel channel for bolting the unit to its foundation. (See DIMENSIONS.) For ground level installations, precautions should be taken to protect the unit from tampering by or injury to unauthorized persons. Screws and/or latches on access panels will prevent casual tampering. However, further safety precautions such as a fenced-in enclosure or locking devices on the panels may be advisable. A tamper proof kit is available as an option. Check local authorities for safety regulations. ROOFTOP LOCATIONS Choose a spot with adequate structural strength to safely support the entire weight of the unit and service personnel. Care must be taken not to damage the roof. Consult the building contractor or architect if the roof is bonded. Roof installations should have wooden beams (treated to reduce deterioration), cork, rubber, or vibration isolators under the base to minimize vibration. NOISE SENSITIVE LOCATIONS Efforts should be made to assure that the chiller is not located next to occupied spaces or noise sensitive areas where chiller noise level would be a problem. Chiller noise is a result of compressor and fan operation. Considerations should be made utilizing noise levels published in the YORK Engineering Guide for the specific chiller model. If questions arise, contact YORK PROD- UCT MARKETING. 2. Block up the equipment so as to install spring mounts with the pin on top of the housing into the chiller mounting holes. 3. The Mounting Adjustment Nut is inside the isolator mount located just below the top plate of the mount. Turn the nut 2 turns clockwise (down) to load the spring mount at each location. 4. Take additional turns on the Adjustment Nut of each location. 5. Repeat Step No. 3 as many times as necessary to bring the height of the isolator to the proper height. 6. Take additional turns on the mounts at the low side or corner to level the equipment. COMPRESSOR MOUNTING The compressors are mounted on four (4) vibration isolators. (See Fig. 7.) The mounting bolts should NEVER be loosened or adjusted at installation of the chiller. CHILLED LIQUID PIPING GENERAL - When the unit has been located in its final position, the unit liquid piping may be connected. Normal installation precautions should be observed in order to receive maximum operating efficiencies. Piping should be kept free of all foreign matter. All liquid evaporator piping must comply in all respects with local plumbing codes and ordinances. Since elbows, tees and valves decrease pump capacity, all piping should be kept as straight and as simple as possible. Hand stop valves should be installed in all lines to facilitate servicing. SHIPPING BRACES A single painted shipping bracket on the opposite end of the control panel runs diagonally along the end of the unit. This may be removed once the unit is mounted on its foundation, however, it may remain in place. SPRING ISOLATORS (OPTIONAL) When ordered, eight (8) spring isolators will be furnished. 1. Identify the isolator and locate at the proper mounting point see pages COMPRESSOR VIBRATION ISOLATOR FIG. 7 - COMPRESSOR VIBRATION ISOLATOR 28 YORK INTERNATIONAL

29 FORM NM2 Piping to the inlet and outlet connections of the chiller should include high-pressure rubber hose or piping loops to insure against transmission of water pump vibration. This is optional and the necessary components must be obtained in the field. Drain connections should be provided at all low points to permit complete drainage of the liquid cooler and system piping. A small valve or valves should be installed at the highest point or points in the chilled liquid piping to allow any trapped air to be purged. Vent and drain connections should be extended beyond the insulation to make them accessible. The piping to and from the cooler must be designed to suit the individual installation. It is important that the following considerations be observed: 1. The chilled liquid piping system should be laid out so that the circulating pump discharges directly into the cooler. The suction for this pump should be taken from the piping system return line and not the cooler. This piping scheme is recommended, but is not mandatory. Keep in mind that a pump whose suction is taken from the evaporator may suffer performance problems. 2. The inlet and outlet cooler connection sizes are 8". 3. A strainer, preferably 40 mesh, should be installed in the cooler inlet line just ahead of the cooler. This is important to protect the cooler from entrance of large particles which could cause damage to the evaporator. 4. All chilled liquid piping should be thoroughly flushed to free it from foreign material before the system is placed into operation. Use care not to flush any foreign material into or through the cooler. 5. As an aid to servicing, thermometers and pressure gauges should be installed in the inlet and outlet water lines. One connection point (plugged) is provided in each cooler nozzle. Thermometers and gauges are not furnished by other suppliers. 6. The chilled liquid lines that are exposed to outdoor ambients should be wrapped with supplemental heater cable and insulated to protect against freezeup during low ambient periods, and to prevent formation of condensation on lines in warm humid climates. 7. A chilled water flow switch, (either by YORK or others) MUST be installed in the leaving water piping of the cooler. There should be a straight horizontal run of at least 5 diameters on each side of the switch. Adjust the flow switch paddle to the size of the pipe in which it is to be installed. (See manufacturer s instructions furnished with the switch.) The switch is to be wired to terminals in the control panel as shown in the WIRING DIAGRAM. WARNING The Flow Switch MUST NOT be used to start and stop the chiller. It is intended only as a safety switch. COMPRESSOR INSULATION In high humidity environments, compressor sweating may be noted. In most applications, this is of no concern. However, if it is undesirable, it is the responsibility of the installer to make provisions to field insulate the compressors or install factory insulation when the option becomes available. Contact YORK Factory Marketing for availability of factory supplied kits. ELECTRICAL WIRING Liquid Chillers are shipped with all factory mounted controls wired for operation. FIELD WIRING - Power wiring must be provided through a fused disconnect switch to the unit terminals (or optional molded disconnect switch) in accordance with N.E.C. or local code requirements. Minimum circuit ampacity and maximum dual element fuse size are given in the ELECTRICAL DATA tables. A , 20 amp source must be supplied for the control panel through a fused disconnect when a control panel transformer (optional) is not provided. Refer to Wiring Diagram (Page 32) in this manual or Form W1. Affiliated apparatus, such as chilled water flow switch, auxiliary contacts from the chilled water pump starter, alarms, etc., should be interlocked into the control panel circuit. These field modifications may be made as shown on the WIRING DIAGRAM. MULTIPLE UNITS For increased compressor protection and to reduce power inrush at start-up on multiple chiller installations, provisions must be made to prevent simultaneous startup of two or more units. Also, some method must be employed to automatically cycle one or more of the units on or off to permit more efficient operation at part load conditions. YORK INTERNATIONAL 29

30 WEIGHT DISTRIBUTIONS AND ISOLATOR LOCATION CHILLERS WITH ALUMINUM CONDENSER COILS MODEL OPERATING WEIGHT DISTRIBUTION (LBS.) AND ISOLATOR LOCATION A B C D E F G H YEAS YEAS YEAS YEAS YEAS YEAS YEAS YEAS YEAS A B C D E F G H CP-2-31 TYPE & SIZE MAX. LOAD LBS. (Kg) SPRING COLOR DEFL IN. (MM) CP (997.9) GRAY.83 (21.0) 30 YORK INTERNATIONAL

31 FORM NM2 CHILLERS WITH COPPER CONDENSER COILS MODEL OPERATING WEIGHT DISTRIBUTION (LBS.) AND ISOLATOR LOCATION A B C D E F G H YEAS YEAS YEAS YEAS YEAS YEAS YEAS YEAS YEAS A B C D E F G H CP-2-31 TYPE & SIZE MAX. LOAD LBS. (Kg) SPRING COLOR DEFL IN. (MM) CP (997.9) GRAY.83 (21.0) YORK INTERNATIONAL 31

32 WIRING DIAGRAM ACROSS-THE-LINE START NOTE: 1. Field wiring to be in accordance with the current edition of the National Electrical Code as well as all other applicable codes and specifications. 2. Numbers along the right side of a diagram are line identification numbers. The numbers at each line indicate the line number location of relay contacts. An underlined contact location signifies a normally closed contact. Numbers adjacent to circuit lines are the circuit identification numbers. 3. Any customer supplied contacts must be suitable for switching 24VDC. (Gold contacts recommended). Control Wiring must not be run in the same conduit with any line voltage wiring. 4. To cycle unit on and off automatically with contact shown, install a cycling device in series with the flow switch (FSLW). See Note 3 for contact rating and wiring specifications. Also refer to cautions on the following page. 5. To stop unit (Emergency Stop) with contacts other than those shown, install the stop contact between 5 and 1. If a stop device is not installed, a jumper must be connected between terminals 5 and 1. Device must have a minimum contact rating of 100VA at 115 volts A.C. 6. Alarm contacts are for annunciating alarm/unit malfunction contacts are rated at 115V, 100VA, resistive load only, and must be suppressed at load by user. 7. See Installation, Operation, and Maintenance Manual when optional equipment is used. 8. Control panel to be securely connected to earth ground. 9. Use 2KVA transformer in optional transformer kit unless there are optional oil separator sump heaters which necessitates using a 3 KVA transformer. FIG. 8 - ELEMENTARY DIAGRAM - ACROSS-THE-LINE START 32 YORK INTERNATIONAL

33 FORM NM2 CONTROL POWER SUPPLY UNIT VOLTAGE CONTROL POWER SUPPLY MAX. MIN. DUAL CIRCUI ELEMENT T AMP. FUSE SIZE NON- FUSED DISC. SWITCH SIZE ALL MODELS W/O TRANS /60 20A 20A, 250V 30A, 240V CAUTION: No Controls (relays, etc.) should be mounted in the Smart Panel enclosure or connected to power supplies in the control panel. Additionally, control wiring not connected to the Smart Panel should not be run through the cabinet. This could result in nuisance faults. CAUTION: Any inductive devices (relays) wired in series with the flow switch for start/stop, into the Alarm circuitry, or pilot relays for pump starters wired through motor contactor auxiliary contacts must be suppressed with YORK P/N suppressor across the relay/contactor coil which activates the contacts. Any contacts connected to flow switch inputs or BAS inputs on terminals of TB3, or any other terminals, must be suppressed with a YORK P/N suppressor across the relay/contactor coil which activates the contacts. CAUTION: Control wiring connected to the control panel should never be run in the same conduit with power wiring. FIG. 8 - CONTINUED YORK INTERNATIONAL 33

34 CONNECTION DIAGRAM (SYSTEM WIRING) FIG. 9 - SYSTEM WIRING 34 YORK INTERNATIONAL

35 FORM NM2 COMPRESSOR TERMINAL BOX ACROSS-THE-LINE START WYE-DELTA START FIG. 9 - CONTINUED YORK INTERNATIONAL 35

36 WYE-DELTA START NOTE: 1. Field wiring to be in accordance with the current edition of the National Electrical Code as well as all other applicable codes and specifications. 2. Numbers along the right side of a diagram are line identification numbers. The numbers at each line indicate the line number location of relay contacts. An underlined contact location signifies a normally closed contact. Numbers adjacent to circuit lines are the circuit identification numbers. 3. Any customer supplied contacts must be suitable for switching 24VDC. (Gold contacts recommended). Control Wiring must not be run in the same conduit with any line voltage wiring. 4. To cycle unit on and off automatically with contact shown, install a cycling device in series with the flow switch (FSLW). See Note 3 for contact rating and wiring specifications. Also refer to cautions on the following page. 5. To stop unit (Emergency Stop) with contacts other than those shown, install the stop contact between 5 and 1. If a stop device is not installed, a jumper must be connected between terminals 5 and 1. Device must have a minimum contact rating of 100VA at 115 volts A.C. 6. Alarm contacts are for annunciating alarm/unit malfunction contacts are rated at 115V, 100VA, resistive load only, and must be suppressed at load by user. 7. See Installation, Operation, and Maintenance Manual when optional equipment is used. 8. Control panel to be securely connected to earth ground. 9. Use 2KVA transformer in optional transformer kit unless there are optional oil separator sump heaters which necessitates using a 3 KVA transformer. FIG ELEMENTARY DIAGRAM - WYE-DELTA START 36 YORK INTERNATIONAL

37 FORM NM2 CONTROL POWER SUPPLY UNIT VOLTAGE CONTROL POWER SUPPLY MIN. CIRCUI T AMP. MAX. DUAL ELEMENT FUSE SIZE NON- FUSED DISC. SWITCH SIZE ALL MODELS /60 20A W/O TRANS. 20A, 250V 30A, 240V CAUTION: No Controls (relays, etc.) should be mounted in the Smart Panel enclosure or connected to power supplies in the control panel. Additionally, control wiring not connected to the Smart Panel should not be run through the cabinet. This could result in nuisance faults. CAUTION: Any inductive devices (relays) wired in series with the flow switch for start/stop, into the Alarm circuitry, or pilot relays for pump starters wired through motor contactor auxiliary contacts must be suppressed with YORK P/N suppressor across the relay/contactor coil which activates the contacts. Any contacts connected to flow switch inputs or BAS inputs on terminals of TB3, or any other terminals, must be suppressed with a YORK P/N suppressor across the relay/contactor coil which activates the contacts. CAUTION: Control wiring connected to the control panel should never be run in the same conduit with power wiring. FIG CONTINUED YORK INTERNATIONAL 37

38 ACROSS-THE-LINE CONNECTION DIAGRAM FIG CONNECTION DIAGRAM - ACROSS-THE-LINE 38 YORK INTERNATIONAL

39 FORM NM2 FIG CONTINUED YORK INTERNATIONAL 39

40 WYE-DELTA CONNECTION DIAGRAM FIG CONNECTION DIAGRAM - WYE-DELTA 40 YORK INTERNATIONAL

41 FORM NM2 FIG CONTINUED YORK INTERNATIONAL 41

42 UNIT CONTROLS AND OPERATION #28164 FIG Millennium CONTROL CENTER INTRODUCTION The YORK Millennium Computer Control Center is a microprocessor based control system capable of multicircuit control to maintain chilled liquid temperature and provide safety control. A 40 character display (2 lines of 20 characters) allows the operator to display system operating parameters as well as access programmed information already in memory. A keypad for programming and accessing setpoints, pressures, temperatures, motor current, cutouts, daily schedule, options, and fault information is provided. A master switch is available to activate or de-activate the chiller system. Separate system (SYS) switches for each refrigerant system (up to 4) are provided on the Microprocessor Board. Remote cycling, current limiting, and chilled water temperature reset can be accomplished by user supplied dry contacts. Compressor starting, stopping, loading and unloading decisions are performed by the Microprocessor to maintain leaving water temperatures. These decisions are a function of temperature deviation from setpoint and the rate of change of temperature. MICROPROCESSOR BOARD The Microprocessor Board is the controller and decision maker in the control panel. System inputs from pressure transducers and temperature sensors are connected directly to the Microprocessor Board. Other inputs from the I/O Expansion Board such as slide valve position, oil temperature, etc. are multiplexed on the Expansion Board and are also sent to the Microprocessor Board. The Microprocessor Board circuitry multiplexes all of these analog inputs, digitizes them, and constantly scans them to keep a constant watch on chiller operating conditions. From this information, the Microprocessor then issues commands to the Relay Output Board to activate and de-activate contactors, solenoids, etc. for chilled liquid control and safety control. 42 YORK INTERNATIONAL

43 FORM NM2 Keypad commands are acted upon by the micro to change setpoints, cut-outs, scheduling, operating requirements, and to provide displays. A +12VDC REG supply voltage from the Power Supply Board is converted to +5V REG by a voltage regulator located on the Microprocessor Board. This voltage is used to operate the integrated circuitry on the board. Four system switches located on the Microprocessor Board activate and deactivate the individual systems (compressors). I/O EXPANSION BOARD The I/O Expansion Board allows additional analog inputs to be tied to the Microprocessor Board. Without this board, the Microprocessor is limited to a specific number of individual inputs that can be connected without enlarging of the board. The expansion board is basically a multiplexer that allows a group of inputs to be connected to the expansion board and then rout these inputs to the Microprocessor Board on a single data line. The individual inputs are multiplexed according to the selection made by the Microprocessor by means of address lines. Signals routed through the I/O Expansion Board include Discharge Temperature, Oil Temperature, and Optional Mixed Water Temperature. POWER SUPPLY BOARD The on-board switching power supply protected by fuse 2 FU converts 24VAC from the 2T transformer to +12V REG which is supplied to the Microprocessor Board, Relay Output Board, and the 40 character display to operate the integrated circuitry. 24VAC is filtered, but not regulated, to provide unregulated +24VDC to supply the flow switch, PWM remote temperature reset, PWM remote current reset, lead / lag select, and remote print circuitry which is available to be used with user supplied contacts. 24VAC is also filtered and regulated to +24VDC to be used by the optional BAS Circuit Boards for remote temperature or remote current reset. Individual rectifier and filtering circuits are present which receive the C.T. signals for each phase of motor current on each compressor. These circuits rectify and filter the signals to variable DC. A phase rotation circuit for each compressor is also present to assure that the screw compressors do not run in the wrong direction. All of these signals are sent to the I/O Expansion Board which multiplexes them and then feeds them to the Microprocessor Board. RELAY OUTPUT BOARD Two Relay Output Boards are required to operate the chiller. These boards convert 0-12VDC logic levels outputs from the Microprocessor Board to 115VAC levels used by motor contactors / starters, solenoid valves, expansion valves, etc. to control system operation. The common side of all relays on the Relay Output Board is connected to +12VDC REG. The open collector outputs of the Microprocessor Board energize the DC relays or triacs by pulling the other side of the relay coil to ground. When not energized, both sides of the relay coils or triacs will be at +12VDC potential. Triacs are used for load and unload slide valve solenoids as well as liquid line solenoid or electronic expansion valves when fitted. Triacs are more suitable than relays when high frequency switching is required. CURRENT TRANSFORMER (C.T.) C.T. s on each of the 3 phases of the power wiring of each motor send AC signals proportional to motor current to the Power Supply Board which rectifies and filters the signals to variable DC Voltage (analog). These analog levels are then fed to the Microprocessor Board to allow it to monitor motor currents for low current, high current, imbalanced current, and single phasing. 40 CHARACTER DISPLAY The 40 Character Display (2 lines of 20 characters) is a liquid crystal display used for displaying system parameters and operator messages. The display has a lighted background for night viewing as well as a special feature which intensifies the display for viewing in direct sunlight. KEYPAD An operator keypad allows complete control of the system from a central location. The keypad offers a multitude of commands available to access displays, program setpoints, and initiate system commands. BATTERY BACK-UP The Microprocessor Board contains a Real Time Clock integrated circuit chip with an internal battery back-up. The purpose of the battery back-up is to assure any programmed values (setpoints, clock, cut-outs, etc.) are not lost during a power failure regardless of the time involved in a power outage or shutdown period. YORK INTERNATIONAL 43

44 #28164 FIG MICROCOMPUTER CONTROL CENTER 44 YORK INTERNATIONAL

45 FORM NM2 SYS 2 FAN OVERLOADS 1 FU 2 FU SYS 1 FAN OVERLOADS SYS 2 FAN CONTACTORS 2A SYS 2 TRANSITION CONTACTOR TB1 115VAC, ALARM, EVAP PUMP USER CONNECTION TERMINALS SYS 2 WYE-DELTA START RESISTORS SYS 1 WYE-DELTA START RESISTORS SYS 1 FAN CONTACTORS 1A SYS 1 TRANSITION CONTACTOR SYS 2 4, 5 & 6 C.T. S (POWER SUPPLY BOARD) SYS 1 1, 2 & 3 C.T. S 2 TR (POWER SUPPLY BOARD) 1 CR 1 TR 2 CR SYS 2 10, 11 & 12 C.T S (MOTOR OVERLOAD) SYS 1 7, 8 & 9 C.T. S (MOTOR OVERLOAD) SYS 2 POWER WIRING CONNECTIONS NOTE: SYS 2 CONTACTORS NOT VISABLE EARTH GROUND CONNECTIONS SYS 1 POWER WIRING CONNECTIONS NOTE: SYS 2 CONTACTORS NOT VISABLE #27963 FIG WYE-DELTA START POWER PANEL YORK INTERNATIONAL 45

46 "DISPLAY" KEYS DISPLAY KEYS #28164 FIG "DISPLAY" KEYS GENERAL The "DISPLAY" keys allow the user to retrieve system pressures, system motor currents, chilled liquid temperatures, saturated temperatures, superheat temperatures, outdoor ambient temperature, compressor running times, number of compressor starts, and option information on the chiller package. This data is useful for monitoring chiller operation, diagnosing potential future problems, troubleshooting, and commissioning the chiller. Displayed data will be real-time data displayed on a "40" character display consisting of 2 lines of 20 characters. The display will update about every "2" seconds. Each of the keys and an example of the typical corresponding display messages will be discussed in the text which follows. Chilled Liquid Temps CHILLED LIQUID TEMPS A display indicating chiller leaving and return water temperature is provided when the key is pressed. L W T = F R W T = F The minimum limit on the display is 9.1 F (-12.7 C). The maximum limit on the display is 84.2 F (29.0 C). When a "DISPLAY" key is pressed, the corresponding message will be displayed and will remain on the display until another key is pressed. Ambient Temp AMBIENT TEMP Display Messages may show characters indicating "greater than" (>) or "less than" (<). These characters indicate the actual values are greater than or less than the limit values which are being displayed. If a message is required to be updated faster than every 2 seconds, the appropriate key for the desired display may be pushed and held. Updating will be at 0.4 second intervals. The outdoor ambient temperature is displayed when this key is pressed. A M B I E N T A I R = F The minimum limit on the display is -4.6 F (-20.3 C). The maximum limit on the display is F (58.8 C). 46 YORK INTERNATIONAL

47 FORM NM2 System 1 Pressures / Temperatures SYSTEM 1 PRESS/TEMP S Y S 1 S L I D E V A L V E P O S I T I O N = % Oil pressure, suction pressure, discharge pressure, suction temperature*, discharge temperature, oil temperature, saturated discharge temperature, saturated suction temperature, slide valve position and superheat on System 1 will be displayed when this key is repetitively pressed. The key must be pressed 6 times to scroll through the 6 displays required to display these operating parameters. Temperatures and pressures may be measured directly by transducers and temperature sensors. Others are computed from these measurements: Differential oil pressure is measured by subtracting oil pressure measured by a transducer located in the oil line after the oil filter from the discharge pressure. (Oil in the oil separator is at discharge pressure.) Ideally, oil injected after the filter, is at discharge pressure. This makes ideal differential oil pressure 0 PSID. However, a pressure drop occurs across the oil filter. Typically, the drop will be 0-10 PSID. As the filter becomes clogged, oil pressure will eventually rise above 40 PSID. Saturated Discharge Temperature is computed by converting discharge pressure to temperature. Saturated Suction Temperature is computed by converting suction pressure to temperature. Slide Valve Position is computed internally by an algorithm in the micro based on average % FLA motor current, programmed motor current equal to 100% FLA, actual condensing temperature, and programmed condensing temperature for a particular chiller model. NOTE: Slide valve position is approximate. Superheat is computed by subtracting saturated suction temperature from suction temperature. Shown below are the 6 pressure / temperature displays: S Y S 1 O I L = 5 0 P S I D S P = 5 5 D P = P S I G S Y S 1 S U C = F D S C H = F O I L T E M P 1 = F S A T D I S H 1 = F S A T S U C T 1 = F S Y S # 1 S U P E R H E A T = F Minimum and maximum limits or values on the displays are shown below. When a minimum limit or value is exceeded, a "<" sign will appear before the numerical value. In the case of maximum limits or values, exceeding them will cause a ">" sign to appear. NOTE: Minimum and maximum values may change as software (EPROM) revisions are made. MIN. LIMITS MAX. LIMITS OIL PRESSURE 208 PSID 0 PSID (O BARD) SUCTION PRESSURE 0 PSIG (O BARG) 199 PSIG (13.7 BARG) DISCHG. PRESSURE 0 PSIG (O BARG) 399 PSIG (27.5 BARG) SUCTION TEMP. *9.0 F (-12.8 C) 84.2 F (29.0 C) DISCHARGE TEMP F (4.6 C) F (150.3 C) OIL TEMP F (4.6 C) F (115.6 C) SAT. DISCHG. TEMP F (-40.6 C) F (60.3 C) SAT. SUCTION TEMP F (-40.6 C) F (38.5 C) SLIDE VALVE POS 0% 100% SUPERHEAT *-81.5 F (-63.1 C) 60.9 F (16.1 C) * NOTE: Below 9.0 F (-12.8 C), the Suction Temp. display will disappear. This will in turn cause the Superheat display to disappear. System 2 Pressures / Temperature SYSTEM 2 PRESS/TEMP Oil pressure, suction pressure, discharge pressure, suction temperature**, discharge temperature, oil temperature, saturated discharge temperature, saturated suction temperature, slide valve position, and superheat on system 2 will be displayed when this key is pressed. The key must be pressed 6 times to scroll through the 6 displays required to display these operating parameters. Temperatures and pressures may be measured directly by transducers and temperature sensors. Others are computed from these measurements: Differential oil pressure is measured by a subtract - ing oil pressure measured by a transducer located in the oil line after the filter, from the discharge pressure. (Oil in the oil separator is at discharge pressure.) Ideally, oil injected after the filter, is at discharge pressure. This makes ideal differential oil pressure 0 PSID. However, a pressure drop occurs across the oil filter. Typically, the drop will be 0-10 PSID. As the filter becomes clogged, oil pressure will eventually rise above 40 PSID. Saturated Discharge Temperature is computed by converting discharge pressure to temperature. YORK INTERNATIONAL 47

48 Saturated Suction Temperature is computed by converting suction pressure to temperature. Slide Valve Position is computed internally by an algorithm in the micro based on % FLA motor current, actual condensing temperature, and programmed condensing temperature for a particular chiller model. NOTE: Slide valve position is approximate. Superheat is computed by subtracting saturated suction temperature from suction temperature. Shown below are the 6 pressure / temperature displays (Also see Sys 1 information on previous page): S Y S 2 O I L = 5 2 P S I D S P = 5 9 D P = P S I G S Y S 2 S U C = F D S C H = F O I L T E M P 2 = F % Motor Current % MOTOR CURRENT Compressor current in amps, % FLA, individual % FLA of each phase, ISN current limit, EMS current limit, and ISN lag compressor start % will be displayed when this key is pressed. The key must be pressed 5 times to scroll through the 5 displays related to motor current. An example of each display is shown below along with an explanation of its meaning. C O M P 1 = A M P S % F L A C O M P 2 = A M P S 9 7 % F L A This display provides a readout of the approximate % FLA current as measured by the 3 C.T. s and the equivalent approximate full load amps. NOTE: Due to typical large variations in discharge pressure, a compressor running "fully loaded" may run over a wide range of currents and % FLA s. Also, FLA is approximately equal to 1.2 x RLA. This means amps equal to RLA of the compressor will only be approximately 80% FLA. S A T D I S H 2 = F S A T S U C T 2 = F S Y S 2 S L I D E V A L V E P O S I T I O N = % S Y S 2 S U P E R H E A T = F Minimum and maximum limits on the displays are shown below. When a minimum value is exceeded, a "<" sign will appear before the numerical value. In the case of maximum limits, exceeding them will cause a ">" sign to appear. NOTE: Minimum and maximum values may change as software (EPROM) revisions are made. MIN. LIMITS MAX. LIMITS OIL PRESSURE 208 PSID 0 PSID (O BARD) SUCTION PRESSURE 0 PSIG (O BARG) 199 PSIG (13.7 BARG) DISCHG. PRESSURE 0 PSIG (O BARG) 399 PSIG (27.5 BARG) SUCTION TEMP. **9.0 F (-12.8 C) 84.2 F (29.0 C) DISCHARGE TEMP F (4.6 C) F (150.3 C) OIL TEMP F (4.6 C) F (115.6 C) SAT. DISCHG. TEMP F (-40.6 C) F (60.3 C) SAT. SUCTION TEMP F (-40.6 C) F (38.5 C) SLIDE VALVE POS 0% 100% SUPERHEAT **-81.5 F (-63.1 C) 60.9 F (16.1 C) **NOTE: Below 9.0 F (-12.8 C), the Suction Temp. display will disappear. This will in turn cause the Superheat display to disappear. C O M P 1 = A V G ; P H L, 1, 2, ; 9 9, 1 0 1, % F L A C O M P 2 = A V G ; P H L, 1, 2, ; 9 7, 9 7, 9 8 % F L A These two displays show the approximate average current (% FLA) and the approximate % FLA of each individual phase (L1, L2, and L3) on each compressor. NOTE: Due to typical large variations in discharge pressure, a compressor running "fully loaded" may run over a wide range of currents and % FLA s. Also, FLA is approximately equal to 1.2 x RLA. This means amps equal to RLA of the compressor will only be approximately 80% FLA. I S N C R N T L I M I T : N O N E E M S C R N T L I M I T : N O N E Demand limit can be accomplished remotely by a YORK ISN system or an external PWM (dry contact closure) from an EMS system connected to the micro. This display shows the % current limiting that may be in effect from these devices. I S N L A G C O M P R E S S O R S T A R T % N O N E This display indicates the ISN programmed value of % FLA of the lead compressor, where the lag compressor will start. This is user selectable. The lower the value of "START %", the less loaded the lead compressor will 48 YORK INTERNATIONAL

49 FORM NM2 be when the lag is called to start. See page 62 for more information. Operating Hours Start Counter OPERATING HOURS START COUNTER Accumulated running hours and starts on each compressor is displayed. The hours counter for an individual system count to a total of 99,999 hours before rollover. A total of 99,999 starts can be logged on a system before the start counter will rollover. H R S 1 = 1 4 3, 2 = S T R 1 = 1 1 7, 2 = The numbers "1" and "2" on the display indicate compressor #1 and compressor #2. These counters are zeroed at the factory, but may indicate run time and number of starts logged during factory testing prior to shipment. Options OPTIONS The "OPTIONS" key provides a display of options which have been selected by the user. These options are selected by the S1 Dip Switch on the Microprocessor Board (Fig. 17). Proper programming of the switch is important during the commissioning of the chiller. The "OPTIONS" display allows a means of verifying the Dip Switch positions without looking at or handling the Microprocessor Board. It also eliminates visual inspection of the sometimes difficult to determine Dip Switch position. When the "OPTIONS" key is pressed, the following message will first be displayed for 3 seconds: T H E F O L L O W I N G A R E P R O G R A M M E D "8" Option Messages will then follow. Each will be displayed for 3 seconds before the next display is automatically indexed. When all messages are displayed, the display message will automatically change to show a chiller "STATUS" message, just as if the "STATUS" key was pressed. Refer to Table 1 for a list of the displays and the corresponding switch positions in the order they appear. Two possible messages may appear for each of the eight messages depending on the Dip Switch position. A detailed explanation of the meaning of each message and a guide to programming the associated switch is provided on page 50. Fig. 17 shows the location and verification of switch positioning of S1. TABLE 1 _ SWITCH POSITION AND DISPLAY DISPLAY/ SWITCH 1 SWITCH "OPEN" MESSAGE W A T E R C O O L I N G SWITCH "CLOSED" MESSAGE B R I N E C O O L I N G S T A N D A R D L O W A M B I E N T A M B I E N T C O N T R O L L O C A L C O N T R O L R E M O T E C O N T R O L M O D E M O D E T H E R M A L E X P A N S I O N T H E R M A L E X P A N S I O N V A L V E S V A L V E S E N G L I S H U N I T S S I U N I T S R E A D O U T R E A D O U T A C R O S S - T H E - L I N E W Y E D E L T A M O T O R S T A R T I N G M O T O R S T A R T I N G M A N U A L A U T O M A T I C L E A D / L A G L E A D / L A G R E F R I G E R A N T T Y P E R E F R I G E R A N T T Y P E R A R 2 2 YORK INTERNATIONAL 49

50 TOP VIEW DIMPLE AT TOP EPROM TOP SIDE RTC SIDE VIEW S1 "OPEN" POSITION (LEFT SIDE OF SWITCH IS PUSHED DOWN) "CLOSED" POSITION (RIGHT SIDE OF SWITCH IS PUSHED DOWN) #26001 FIG DIP SWITCH LOCATION AND POSITION SWITCH 1 SWITCH 2 OPEN: OPEN: W A T E R C O O L I N G This mode is used for most applications and allow the chilled liquid temperature setpoint to be programmed from F. Selecting this mode also fixes the Low Chilled Liquid Cut-out at 36.0 F and the Suction Pressure Cut-out at 44 PSIG. CLOSED: S T A N D A R D A M B I E N T This mode fixes the low ambient cut-out at 25 F and must be selected when a Low Ambient Kit is NOT installed. CLOSED: B R I N E C O O L I N G This mode is used primarily for chilled liquid temperature setpoints below 38 F. The chilled liquid setpoint can be programmed from F. This mode also allows the Low Chilled Liquid Cut-out to be programmable from 8-36 F and the Suction Pressure Cut-out from PSIG. L O W A M B I E N T C O N T R O L A Low Ambient Kit MUST be installed to use this mode. The low ambient cut-out is programmable from 0-50 F. 50 YORK INTERNATIONAL

51 FORM NM2 SWITCH 3 SWITCH 5 OPEN: OPEN: L O C A L C O N T R O L M O D E "LOCAL" mode allows an ISN or an RCC (Remote Control Center) option panel to receive chiller data from the chiller through the RS-485 port, but not change programmable setpoint values remotely. CLOSED: E N G L I S H U N I T S R E A D O U T Display messages will show units of measure in English units ( F, PSI, etc.). CLOSED: R E M O T E C O N T R O L M O D E "REMOTE" mode allows an ISN or an RCC (Remote Control Center) option panel to receive chiller data from the chiller through the RS-485 port. This mode will also allow loading, unloading, shutdown, Leaving Water Setpoint Reset, Current Limit Setpoint, and Lag Start Setpoint from an ISN or RCC. If communications is lost to the ISN or RCC, the micro will run the chiller on the micro panel programmed values. S I U N I T S R E A D O U T Display messages will show units of measure in Standard Imperial (Metric) units ( C, BAR, etc.) OPEN: SWITCH 4 OPEN: SWITCH 6 T H E R M A L E X P A N S I O N V A L V E S This switch is presently disabled. In the future, it will allow selection of control from either thermal expansion valves or electronic expansion valves. CLOSED: A C R O S S - T H E - L I N E M O T O R S T A R T I N G This mode MUST be selected for chillers with Acrossthe-line starters where only one contactor per compressor is present in the power panel. CLOSED: T H E R M A L E X P A N S I O N V A L V E S This switch is presently disabled. In the future, it will allow selection of control from either thermal expansion valves or electronic expansion valves. W Y E D E L T A M O T O R S T A R T I N G This MUST be selected for chillers with Wye-Delta starters where three contactors and wire wound power resistors are present for each compressor in the power panel. YORK INTERNATIONAL 51

52 SWITCH 7 SWITCH 8 OPEN: OPEN: M A N U A L L E A D / L A G R E F R I G E R A N T T Y P E R A SYS 1 can be selected as the lag compressor by closing a user supplied contact between terminals 13 and 19. See Fig. 17. CLOSED: This switch position MUST be selected, if the refrigerant type is R134A. Incorrect selection of this switch may cause catastrophic damage to the chiller. CLOSED: A U T O M A T I C L E A D / L A G R E F R I G E R A N T T Y P E R 2 2 In this mode, the micro determines which compressor is assigned to the lead and the lag. A new lead / lag assignment is made whenever a compressor shuts down. The micro will then assign the "lead" to the compressor with the shortest anti-recycle time. If both compressors are shut down, the micro will start the first available compressor in an effort to maintain control of temperature as soon as possible. This switch position MUST be selected, if the refrigerant type is R22. Incorrect selection of this switch may cause catastrophic damage to the chiller. 52 YORK INTERNATIONAL

53 FORM NM2 "STATUS" KEY STATUS KEY ##28164 FIG "STATUS" KEY GENERAL Pressing the "STATUS" key will enable the operator to determine current chiller operation status as a whole and as individual systems. The messages displayed will include running status, cooling demand, fault status, external cycling device status, load limiting, and anti-recycle timer status. The display will be a single message relating to the highest priority message as determined by the microprocessor. Status messages fall into the categories of General and Fault Status with each of the categories discussed below. GENERAL STATUS MESSAGE Each of the general status messages with a description of its meaning will follow. In the case of messages which apply to individual systems, SYS 1 and SYS 2 messages will both be displayed and may be different. "X" s in the sample displays indicate numerical values that will appear in the actual displays. U N I T S W I T C H I S I N T H E O F F P O S I T I O N This message informs the operator that the "UNIT" switch on the Control Panel is in the OFF position which will not allow the chiller to run. D A I L Y S C H E D U L E S H U T D O W N The DAILY SCHEDULE SHUTDOWN message indicates that the daily schedule programmed into the "CLOCK" "SET SCHEDULE / HOLIDAY" is keeping the chiller from running. S Y S 1 S Y S 2 N O R U N P E R M N O R U N P E R M Run Permissive is an indicator that an external cycling contact or flow switch connected in series with terminals 13 and 14 is open. Whenever the contact(s) is (are) open, the NO RUN PERM will be displayed. S Y S 1 S Y S 2 N O C O O L L O A D N O C O O L L O A D This message informs the operator that the chilled liquid temperature is below the point (determined by the setpoint and control range) that the micro will bring the lead system on, and / or that the micro has not loaded the system far enough into the loading sequence to be ready to bring the lag system ON. The lag system will display this message until the loading sequence is ready for the lag system to start. YORK INTERNATIONAL 53

54 S Y S 1 S Y S 2 C O M P R U N N I N G C O M P R U N N I N G S Y S 1 D S C H L I M I T I N G S Y S 2 D S C H L I M I T I N G The COMP RUNNING message indicates that the respective compressor is running due to demand. S Y S 1 A R T I M E R X X X S S Y S 2 A R T I M E R X X X S The anti-recycle timer message shows the amount of time left on the respective anti-recycle timer. Discharge Pressure Limiting takes affect when discharge pressure nears the point at which the high pressure cut-out will shut the system down causing total loss of cooling. When this message appears, discharge pressure has exceeded the "user" programmable threshold and the micro is unloading the affected system to prevent shutdown on a manual high pressure cut-out. Reloading will take place when discharge pressure has dropped 60 PSIG below the threshold. S Y S 1 S Y S 2 A C T I M E R X X S A C T I M E R X X S S Y S 1 S U C T L I M I T I N G S Y S 2 S U C T L I M I T I N G The anti-coincident timer is a software feature that guards against 2 compressors starting simultaneously. This assures instantaneous starting current does not become excessively high due to simultaneous starts. The micro limits the time between compressor starts to 1 minute regardless of demand and anti-recycle timers that are timed out. The time shown on the anti-coincident timer is the time left on the timer before the respective system will start. It will only appear when the anti-recycle timer has timed out. S Y S 1 C R N T L I M I T I N G S Y S 2 C R N T L I M I T I N G The Motor Current Limiting message indicates a system is being unloaded by the micro even though demand requires loading. Used as a safety, this feature assures that motor current does not become excessively high causing compressor shutdown. The safety will activate when the user programmed threshold is exceeded, providing as much capacity as possible up to the limit programmed. Additional loading will take place when motor current drops below the threshold. In most circumstances, this safety will never activate if current limiting is programmed for 100% -115%. However, in extremely high ambients, high chilled liquid temperature, and situations where the condenser becomes dirty, the protection provided by this safety will assure that compressor shutdown does not result in total cooling loss by limiting loading until the usually short term situation causing the problem clears. This message also indicates unloading due to current limiting where the user has the programmed unload point set below 100% to utilize the programmable unload for "demand limiting". Resetting of current limit unloading may be done through the "PROGRAM" mode on the Control Panel. SUCTION LIMITING is only operable when optional electronic expansion valves are added to the chiller. If suction pressure exceeds the programmed pressure, the micro will allow superheat to rise above the setpoint in an attempt to reduce suction pressures. This is done to assure that adequate motor cooling is provided. Normally, the default value is sufficient and programming is not necessary. Details on programming this feature are outlined on page 61. S Y S 1 E M S L I M I T I N G S Y S 2 E M S L I M I T I N G This message indicates the current limiting is in effect through the Current Limit PWM input on Terminals 13 and 16 of the Microprocessor Board. As long as this input is activated, the micro will not allow loading beyond the PWM % that has been sent to the microprocessor through the PWM input. Generally, this input is used for purposes of demand limit. Details of the use of this feature are outlined on page 64. S Y S 1 I S N L I M I T I N G S Y S 2 I S N L I M I T I N G ISN LIMITING allows load limiting through an ISN System. This feature controls loading under a number of ISN programmable values, enhancing the flexibility of controlling the chiller to obtain desired results in the total building control scheme. S Y S 1 S Y S S W I T C H O F F S Y S 2 S Y S S W I T C H O F F This message informs the operator that the system switch on the Microprocessor Board for the respective system is in the OFF position. The switch for System 1 and System 2 must be in the ON position for the systems to operate. Switches for System 3 and 4 should be 54 YORK INTERNATIONAL

55 FORM NM2 placed in the OFF position on 2 compressor chillers. See Fig. 19 for the location of these switches. R E P R O G R A M T Y P E O F R E F R I G E R A N T T O R U N This message indicates that the type of refrigerant programmed under the "PROGRAM" key does not match the type of refrigerant selected on the S1 dip Switches on the Microprocessor Board. Selections on the S1 Dip Switches on the Microprocessor Board can be viewed by pressing the "OPTIONS" key (Page 49). The chiller will not operate until this situation is corrected. Also see page 59 to change the refrigerant type in the PROGRAM mode. SYSTEM SWITCHES #26001 FIG LOCATION OF THE MICROPROCESSOR BOARD SYSTEM SWITCHES YORK INTERNATIONAL 55

56 FAULT STATUS MESSAGES Thirteen possible fault messages may appear when the "STATUS" key is pressed. Whenever a fault message appears, the safety thresholds on the chiller have been exceeded and the entire chiller or a single system will be shut down and locked out. A detailed explanation of the shutdown thresholds and associated information related to each fault is covered in the SYSTEM SAFETIES section. Chiller shutdown faults will shut the entire chiller down and lock it out, while system shutdown faults will only shut down and lock out the affected system (compressor). A list of the fault messages is shown below: C H I L L E R F A U L T : L O W W A T E R T E M P S Y S 1 H I G H D S C H P R E S S Y S 2 H I G H D S C H P R E S S Y S 1 L O W C U R R / M P / H P S Y S 2 L O W C U R R / M P / H P S Y S 1 H I G H O I L T E M P S Y S 2 H I G H O I L T E M P S Y S 1 H I G H M T R C U R R S Y S 2 H I G H M T R C U R R S Y S 1 H I G H D S C H T E M P S Y S 2 H I G H D S C H T E M P S Y S 1 M T R C U R R U N B A L S Y S 2 M T R C U R R U N B A L C H I L L E R F A U L T : V A C U N D E R V O L T A G E S Y S 1 P H A S E R O T A T I O N S Y S 2 P H A S E R O T A T I O N C H I L L E R F A U L T : L O W A M B I E N T T E M P S Y S 1 L O W S U C T I O N S Y S 2 L O W S U C T I O N C H I L L E R F A U L T : H I G H A M B I E N T T E M P S Y S 1 H I G H O I L D I F F S Y S 2 H I G H O I L D I F F 56 YORK INTERNATIONAL

57 FORM NM2 "ENTRY" KEYS ENTRY KEYS #28164 FIG "ENTRY" KEYS GENERAL The "ENTRY" key allows the user to change numerical values programmed in as chiller setpoints, cut-outs, clock, etc Numerical Keypad The NUMERICAL keypad provides all keys necessary to program numerical values as required into memory. The " *" key is used to designate holidays when programming special start and stop times for designated holidays in the SET SCHEDULE / HOLI- DAY display. The "+/-" key allows programming -C setpoints and cut-outs in the metric display mode. Enter Key ENTER The "ENTER" key must be pushed after any change is made to setpoints, cut-outs, or system clock. Pressing this key tells the micro to accept new values into memory. If this is not done, the new values entered will be lost and the original values will be returned. The "ENTER" key is also used to scroll through available data after any one of the following (4) keys is pressed: PROGRAM SET SCHEDULE /HOLIDAY OPER DATA 4 7 * / _ Cancel Key CANCEL The "CANCEL" key allows the user to change errors in the data being programmed into memory. When the "CANCEL" key is pressed, the cursor will always return to the first character to be programmed in the display message. This allows the operator to begin reprogramming. When the "CANCEL" key is pressed, the values already keyed in will be erased and the original or internally programmed default values will appear. In other instances the display will remain the same and the only reaction will be the cursor returning to the first character. AM/PM Key AM/PM The "AM / PM" key allows the user to change AM / PM while programming the correct time in the SET TIME display. The same key allows changing the AM / PM schedule while programming daily chiller start and stop times in the SET SCHEDULE / HOLIDAY display. Advance Day Key ADVANCE DAY The "ADVANCE DAY" key advances the day when the SET TIME display is being programmed. The day is normally advanced to correspond to the current day of the week. The day will advance one day at a time, each time the key is pressed. HISTORY YORK INTERNATIONAL 57

58 "PROGRAM" KEY PROGRAM KEY #28164 FIG "PROGRAM" KEY PROGRAM KEY - USER PROGRAMMABLE VALUES GENERAL Pushing the "PROGRAM" key allows the user to program "21" system operating values. These values include cut-out points for safeties, anticipatory unload points to avoid faults, and anti-recycle timer duration. After the "PROGRAM" key is pressed, the micro will first respond by displaying the following message: P R O G R A M M O D E Programmable values not password protected are identified by the presence of the cursor under the first digit of the numerical value. Non password protected values may be keyed in by simply typing a new value and pressing the "ENTER" key to program the new value into memory. Failure to press "ENTER" will cause the new value to be lost. To reprogram password protected values where the cursor does not appear, the "PROGRAM" key must first be pressed. The micro will respond by displaying the following message: P R O G R A M M O D E Press the "ENTER" key to access the first programmable display. As the "21" values are displayed, they may be reprogrammed using the "12" "ENTRY" keys. New values will be programmed into memory when the "ENTER" key is pushed. The "ENTER" key must also be used to advance the display on which the operator views the "21" programmable values. Each time the "ENTER" key is pushed, the display will advance to the next programmable value. Some programmable values are password protected due to their critical nature. These are identified by the absence of the cursor when the display is viewed. To access the password protected values, key in the 4 digit code "7396" and press "ENTER". As "7396" is being keyed in, the display will show the digits as. See below: P R O G R A M M O D E Pressing "ENTER", displays the first programmable value. Access to password protected values is indicated by the cursor positioned at the first digit of the numerical value. A new value may be keyed in for each value and placed into memory by pressing "ENTER". After a new value is entered, the display will advance to the next programmable display. 58 YORK INTERNATIONAL

59 FORM NM2 Once accessed, the display will stay in the password protected mode until a "DISPLAY", "PRINT", "SET- POINT", or "CLOCK" key is pressed. If the operator attempts to enter an unacceptable value, the micro will respond with a momentary message indicating the selected value has been ignored. This error message is shown below: O U T O F R A N G E T R Y A G A I N! The "21" programmable displays are shown and described below in the order in which they appear along with the range of values which the microprocessor will accept for each. THE PROGRAMMABLE VALUES UN- DER THE "PROGRAM" KEY MUST BE CHECKED AND PROPERLY PROGRAMMED WHEN COMMIS- SIONING THE CHILLER. FAILURE TO PROPERLY PROGRAM THESE VALUES MAY CAUSE DAMAGE TO THE CHILLER OR OPERATING PROBLEMS. REFRIGERANT TYPE R E F R I G E R A N T T Y P E 2 2 O R The "REFRIGERANT TYPE" display message allows the user to program the chiller for the type of chiller. This MUST be programmed according to the type refrigerant used in the chiller. Failure to program this value correctly will cause catastrophic damage to the chiller. The type of refrigerant used is noted in the Engineering Data stamped on the unit nameplate. See page 4. Whenever R22 is programmed, it is required to first key in a "0". Example: 022. To program the type of refrigerant, access the password protected values as described previously. Key in the type refrigerant and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. NOTE: The type of refrigerant programmed must match the refrigerant selected on the S1 Dip Switches on the Microprocessor Board. These selections can be viewed by pressing the "OPTIONS" key (Page 52). If these two selections do not match, the following message will appear. R E P R O G R A M T Y P E O F R E F R I G E R A N T T O R U N The chiller will not operate until this situation is corrected. DISCHARGE PRESSURE CUT-OUT D I S C H A R G E P R E S S U R E C U T O U T = P S I G The DISCHARGE PRESSURE CUT-OUT is a microprocessor back-up for the mechanical high pressure cut-out located in each refrigerant circuit. Typically chillers with air-cooled condensers should have the cut-out set at 395 PSIG (275 PSIG for R134a). To program the DISCHARGE CUT-OUT, access the password protected values as described previously. Key in the desired discharge pressure cut-out and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. The micro will accept a range of programmable values between PSIG ( PSIG for R134a) for this cut-out. For this cut-out to be functional, the Discharge Pressure Read-out Option must be installed. More details on this safety are provided in the SYSTEM SAFETIES section. LOW AMBIENT CUT-OUT L O W A M B I E N T T E M P C U T O U T = F The LOW AMBIENT CUT-OUT allows the user to select the chiller low ambient temperature cut-out point. If the ambient temperature falls one degree below this point, the chiller will shut down. Restart can occur, if demand allows, when temperature rises more than one degree F above the cut-out. This only applies to outdoor aircooled chillers. For normal ambient applications, the cut-out is set at 25 F and is NOT programmable. However, some users may set the cut-out higher to shut down the chiller and take advantage of other less costly cooling sources. In this case, S1 Dip Switch #2 on the Micro Logic Board must be in the CLOSED position for "Low Ambient Control" which allows programming the cut-out above 25 F. Low ambient operation capability of less than 25 F is standard on the chiller. If low ambient operation is required below 25 F, S1 Dip Switch #2 on the Micro Logic Board must be in the CLOSED position for "LOW AMBIENT CONTROL" which allows programming of the cut-out between 0-50 F. If operation is occasionally needed below 0 F, the cut-out should be set at 00.0 F. YORK INTERNATIONAL 59

60 This will allow operation at any temperature since the micro is only able to recognize temperatures above 1 F and will never display temperatures below 1 F. NOTE: Operation below 0 F may cause nuisance low pressure safety shutdowns. Occasional shutdowns can usually be tolerated since the need for sustained operation at these low temperatures is unlikely and temperatures rarely stabilize for any length of time below 0 F. To program the LOW AMBIENT CUT-OUT, access the password protected values as described previously. Key in the desired low ambient cut-out and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. The micro will accept a range of programmable values between F for this cut-out, if Dip Switch #2 on the Micro Logic Board is in the CLOSED position. In the OPEN position, a fixed 25 F cut-out is recognized. HIGH AMBIENT CUT-OUT H I G H A M B I E N T T E M P C U T O U T = F The HIGH AMBIENT CUT-OUT is selectable to establish the chiller high ambient cut-out point. If the ambient rises more than one degree above this point, the chiller will shut down. Restart can occur when temperature drops more than one degree F below the cut-out. This only applies to outdoor air cooled chillers. This cut-out is normally set at 130 F to allow operation to the absolute maximum temperature capability of the electro-mechanical components. To program the OUTSIDE AIR TEMP HIGH CUTOUT, access the password protected values as described previously. Key in the desired high ambient cutout and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. The micro will accept a range of programmable values between F for this cut-out. DISCHARGE PRESSURE UNLOAD D I S C H A R G E P R E S S U R E U N L O A D = P S I G The DISCHARGE PRESSURE UNLOAD point is a programmable limit to keep the system from faulting on the high discharge pressure cut-out should a system problem or chiller problem occur. A typical problem would be dirty condenser coils. Pressure would rise and eventually cause the chiller to fault causing a total loss of cooling. By unloading the compressors at high discharge pressures, the chiller is allowed to continue to run automatically at reduced capacity until the dirty condenser coils can be attended to. When the unload point is reached, the micro will automatically totally unload the affected compressor. Typical maximum programmed limits would be 375 PSIG for air cooled chillers with a 395 or 405 PSIG high pressure cut-out. Reloading will occur when the discharge pressure drops to 60 PSIG below the programmed unload pressure and will increment loading one stage at a time as indicated by the loading timers. To program the DISCHARGE PRESSURE UNLOAD, access the password protected values as described previously. Key in the desired discharge pressure unload value and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. The micro will accept a range of programmable values between PSIG ( PSIG for R134a) for the unload point. AVERAGE CURRENT UNLOAD A V E R A G E C U R R E N T U N L O A D = % F L A The AVERAGE CURRENT UNLOAD point is a programmable limit designed to assure that the motor current safety does not cause shutdown of the compressor. If motor current rises above the programmed motor current unload point, the micro will automatically begin to unload the affected compressor at 5 second intervals until the current draw on the motor falls below the unload point. This will assure that the motor operates under acceptable conditions insuring maximum motor life. Reloading will occur when the motor average current drops below 90% of the programmed unload point. This feature may also be used in instances where demand limiting is required. By programming the unload point below the % current drawn when the compressors are fully loaded, the compressors will be prevented from fully loading which reduces energy consumption. 60 YORK INTERNATIONAL

61 FORM NM2 To program the MOTOR CURRENT UNLOAD, key in the desired value and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next programmable value. This value is not password protected and can be programmed anytime the "PROGRAM" key is pressed. The micro will accept a range of programmable values between % for the unload point. Keep in mind that the motor current safety will shut the compressor down whenever current exceeds 115%. Typically, this setpoint will be set at %. It is not recommended to program a value greater than 105%. For maximum motor protection, programming for 100% is advisable. NOTE: When programming values from 30-99%, it is required to first key in a "0". Example: 085%. ANTI-RECYCLE TIME A N T I R E C Y C L E T I M E = S E C S The ANTI-RECYCLE TIME selection allows the user to select the compressor anti-recycle time best suited to his needs. Motor heating is a result of inrush current when the motor is started. This heat must be dissipated before another start takes place or motor damage will result. The anti-recycle timer assures the motor has sufficient time to cool before it is again restarted. An adjustable timer allows for the motor cooling required, but gives the user the ability to extend the timer to cut down on cycling. In some applications, fast compressor start response is necessary. In others it is not. These needs should be kept in mind and the timer should be adjusted for the longest period of time tolerable. Although 300 seconds is adequate motor cooling time, longer periods will allow even more heat dissipation, reduce cycling, and possibly increase motor life. 600 seconds is recommended. To program ANTI-RECYCLE TIME, key in the desired value and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. This value is not password protected and can be programmed anytime the "PROGRAM" key is pressed. The micro will accept a range of programmable values between seconds for this operating control. LEAVING WATER TEMP CUT-OUT L E A V I N G W A T E R T E M P C U T O U T = F The LEAVING WATER TEMP CUT-OUT protects the chiller from an evaporator freeze-up should the chilled liquid temperature drop below the freeze point. This situation could occur under low flow conditions or if the Micro Panel SETPOINT values are improperly programmed. Anytime the leaving chilled liquid temperature (water or glycol) drops below the cut-out point, the chiller will shut down. The chiller will be re-enabled when temperature rises more than four degrees above the cut-out. For chilled water applications (WATER COOLING, SW1 CLOSED), the cut-out is automatically set at 36 F and cannot be reprogrammed. This covers applications where leaving water temperatures are not designed to go below 40 F. If the chilled liquid (glycol) temperatures are required below 40 F (BRINE COOLING, SW1 OPEN), the cut-out should be programmed 4 F below the Low Limit Water Temp of the programmed CR (Control Range). See page 79 on Low Limit Water Temp of Control Range (CR). To program the LEAVING WATER TEMP CUT-OUT the BRINE COOLING (SW1, OPEN) must be selected. Also, the password protected PROGRAM values must be accessed as described previously. Key in the desired cut-out value and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next programmable value. The micro will accept a range of programmable values between F for this cut-out. SUCTION PRESSURE CUT-OUT S U C T I O N P R E S S U R E C U T O U T = P S I G The SUCTION PRESSURE CUT-OUT protects the chiller from an evaporator freeze-up should the system attempt to run with a low refrigerant charge. Anytime the suction pressure drops below the cut-out point for 90 seconds, the system will shut down. NOTE: During the first four and a half minutes of operation, operation of this cut-out will differ from the operation outlined above. Details are outlined in the SYSTEM SAFETIES section. For chilled water applications, the cut-out should be set at 44 PSIG. If glycol or brine is utilized with leaving water temperature designs below 40 F, the cut-out should be adjusted according to concentration. A rule-of-thumb cut-out design is to drop the cut-out 1 PSIG below 44 PSIG for every degree of leaving glycol below 40 F. In other words, 30 F glycol requires a 34 PSIG suction pressure cut-out. To program the SUCTION PRESSURE CUT-OUT, access the password protected values as described previously. Key in the suction pressure cut-out value and YORK INTERNATIONAL 61

62 press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. In the WATER COOLING MODE (SW1 OPEN), the cut-out is programmable values between PSIG (19-36 PSIG for R134a). In this mode, 44 PSIG is recommended. In the BRINE COOLING MODE (SW1 CLOSED), the cut-out is adjustable from PSIG ( PSIG for R134a). LAG COMPRESSOR START POINT L A G C O M P R E S S O R S T A R T P O I N T 7 0 % Selection of the LAG COMPRESSOR START POINT % primarily allows the user to either allow the lead compressor to fully load to 99% FLA or Slide Valve, (whichever is programmed, see page 62) before the lag compressor is started or start the lag compressor at a lead compressor % FLA less than 99%. Selecting a LAG COMPRESSOR START POINT % of 99% assures that the lead compressor is fully loaded before the lag compressor is brought on. If very low loads are expected, less compressor cycling will be noted by selecting a high slide valve percentage. 99% would be the recommended % to reduce cycling. If due to system conditions the lead compressor does not reach the programmed %, even though the lead system is fully loaded, the lag compressor will start regardless of the programmed % after 5 minutes of operation whenever the lead compressor cannot bring the LWT to within 2.0 F of the high end of the Control Range (CR). Once the lag compressor is started, equalizing loading and unloading of the two compressors will occur. This assures that the chiller will fully load and maintain chilled liquid temperature. Selecting a LAG COMPRESSOR START POINT % less than 99% increases the efficiency of chiller operation. At lower percentages, the lead compressor is loaded to the programmed % and the lag compressor will come on and be brought up to a % equal to the lead compressor. At this point, the loading of both compressors will be adjusted up or down to maintain capacity and equalize loading on the two compressors. Running both compressors partially loaded makes more efficient use of the evaporator than running one compressor fully loaded with the other idle. Running both compressors partially loaded assures that the entire evaporator is being utilized and is the most efficient condition for operating the chiller system. However, keep in mind that once the lag compressor is started, equalized loading at part load is always maintained by the microprocessor even with the LAG COM- PRESSOR START POINT programmed at 99%. If a % less than 99% is selected for efficiency purposes, a value of 70% is recommended. This will typically assure that the lag compressor will start before the lead is fully loaded. To program the LAG COMPRESSOR START POINT %, key in the desired value and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. This value is not password protected and can be programmed anytime the "PROGRAM" key is pressed. The micro will accept a range of programmable values between 40-99% for this operating control. L A G C O M P R E S S O R D I F F E R E N T I A L O F F 2 0 % This control allows the operator to select the range over which the lead and lag compressor load share equally. Once the lag compressor is brought on and loads up to a % equal to the lead compressor, if demand allows, sharing of the load will continue as the load drops until a programmed differential % below the LAG COMPRES- SOR START POINT % is reached. For example: If a LAG COMPRESSOR START POINT % of 70% is selected, and a LAG COMPRESSOR DIFFERENTIAL OFF % of 50% is selected, the lead and lag compressor will both load share the % (FLA or Slide Valve, whichever is programmed, see page 62) of the lead compressor drops to 20% (70% - 50% = 20%). At this point, the micro will unload only the lag compressor until it reaches a point at which the micro determines it is fully unloaded and load does not require its continued operation and it will cycle off. The larger the % differential programmed, the more efficient the use of the cooler. For efficiency purposes, 50% is recommended. Cycling of the lag compressor will also be minimized since equalized unloading operates over a wider range. A small % differential, will increase cycling and lower efficiency slightly. For example: If 10% LAG COMPRES- SOR DIFFERENTIAL OFF % is selected with a LAG COMPRESSOR START POINT % of 70%, the lag will start when the lead % FLA reaches 70%. The lag loading will be brought up to equalize the lead of 70% if demand requires. Both compressors will increase in loading proportionately as demand increases. When the load drops, both compressors will unload to 60%. At this point, only the lag compressor will be unloaded as demand drops. It will unload until it reaches a point at which the micro determines it is fully unloaded and load does not require 62 YORK INTERNATIONAL

63 FORM NM2 its continued operation and the compressor will be cycled off. A minimum % point is built into the micro to only allow load sharing to operate to a minimum of 20% of the lead compressor. Therefore the LAG COMPRESSOR START POINT % minus the LAG COMPRESSOR DIF- FERENTIAL OFF % cannot be less than 20% or an out of range message will appear. To program the LAG COMPRESSOR DIFFERENTIAL OFF %, key in the desired value and press the "EN- TER" key. The new value will be entered into memory and the display will advance to the next user programmable value. This value is not password protected and can be programmed anytime the "PROGRAM" key is pressed. The micro will accept a range of programmable values between 0-50% for this operating control, provided the LAG COMPRESSOR START POINT % minus the LAG COMPRESSOR DIFFERENTIAL OFF % does not equal less than 20%. T O T A L N U M B E R O F F A N S O N C H I L L E R = 8 F A N S The TOTAL NUMBER OF FANS ON CHILLER is programmable to allow proper fan operation on 8 and 12 fan chillers. Selection should be done by simply counting the fans. NOTE: This must be programmed correctly or improper operation and damage to the chiller may result. To program the TOTAL NUMBER OF FANS ON CHILLER, access the password protected values as described previously. Key in the number of fans, either 8 or 12 and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. NOTE: When programming the chiller for "8" fans, it is required to first key in a "0". Example: 08. FAN CONTROL DISCHARGE PRESSURE SETPOINT F A N C N T R L D S C H P R E S S S E T P O I N T = P S I G The FAN CNTRL DSCH PRESS SET POINT is programmable to allow the operator to program the discharge pressure at which the first pair of fans starts. The first pair of fans will run in the reverse direction. Selection of the discharge pressure should be done keeping in mind oil return and proper TXV operation. Generally, the recommended point of fan starting is 230 PSIG. Too low of a setting will cause low discharge pressures which in turn causes oil return problems and TXV operation problems. Both of these can lead to catastrophic compressor failure. To program the FAN CONTROL DISCHARGE PRES- SURE SETPOINT, access the password protected values as described previously. Key in the pressure setpoint and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. The micro will accept a range of programmable values from PSIG ( PSIG for R134a). After the first pair of reverse fans are brought on, discharge pressure must rise 20 PSIG above the FAN CNTRL DSCH PRESS SETPOINT before a second pair of fans (first pair of forward fans) will be brought on in the forward direction. The pair of reversing fans will turn off at this point. After discharge pressure rises 40 PSIG above the FAN CNTRL DSCH PRESS SETPOINT, the 2nd pair of forward fans will turn on and operate. These are the reversing fans operating in the forward direction. The first pair of forward fans will also continue to run. FAN ON / OFF PRESS DIFF F A N O N / O F F P R E S S D I F F = 5 0 P S I G The FAN ON/OFF PRESS DIFF determines the "OFF" pressure at which each pair of fans will cycle off. If a differential of 50 PSIG is selected, the second pair of forward fans that cycled on (Example: 270 PSIG) will cycle off when discharge pressure drops 50 PSIG below the "ON" pressure (Example: 220 PSIG). The first pair of forward fans to start (Example: 250 PSIG) will cycle off at 50 PSIG below the on pressure (Example: 200 PSIG). When this pair of fans cycles off, the reversing fans will not come on until the pressure reaches the FAN CONTROL DISCHARGE PRESSURE SETPOINT (Example: 230 PSIG). If the reversing fans are operating, they too will turn off on a pressure drop. In the example above, if the reversing fans turned on at 230 PSIG and are operating, they would turn off at 180 PSIG. SYSTEM 1 MOTOR CURR S Y S T E M 1 M O T O R C U R R A M P S = % F L A SYSTEM 1 MOTOR CURR allows the operator to display the approximate current that the motor is drawing YORK INTERNATIONAL 63

64 by pressing the "DISPLAY" key labeled % MOTOR CURRENT. SYSTEM 1 MOTOR CURR also allows the motor current to be programmed at 100% full load to permit the micro to determine slide valve position when controlling loading/unloading. This is important to allow load sharing. Select the actual current at 100% load by selecting the chiller model and voltage from Table 2 and its corresponding AMPS at 100% FLA. To program the SYSTEM 1 MOTOR CURR, access the password protected values as described previously. Key in the current value that equals 100% FLA and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. SYSTEM 2 MOTOR CURR S Y S T E M 2 M O T O R C U R R A M P S = % F L A SYSTEM 2 MOTOR CURR allows the operator to display the approximate current that the motor is drawing by pressing the "DISPLAY" key labeled % MOTOR CURRENT. SYSTEM 2 MOTOR CURR also allows the motor current to be programmed at 100% full load to permit the micro to determine slide valve position when controlling loading/unloading. This is important to allow load sharing. Select the actual current at 100% load by selecting the chiller model and voltage from Table 2 and its corresponding AMPS at 100% FLA. To program the SYSTEM 2 MOTOR CURR, access the password protected values as described previously. Key in the current value that equals 100% FLA and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. LIQUID INJECTION TEMP LIMIT L I Q U I D I N J E C T I O N T E M P L I M I T = F LIQUID INJECTION TEMP LIMIT programs the oil temperature at which the liquid injection solenoid is energized to allow liquid to be injected into the compressor for oil cooling. This assures that temperatures of the oil are maintained low enough to assure proper lubrication and compressor cooling. The recommended program point is 180 F (82.1 C). To program the LIQUID INJECTION TEMP LIMIT, access the password protected values described previously. Key in the value and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next programmable value. SYSTEM 1 COND TEMP If loading/unloading is selected utilizing slide valve %, the design condensing temperature (discharge pressure converted to temperature or CTP) at 100% load must be programmed for each system for the specific model of chiller that is utilized. To program SYSTEM 1 COND TEMP, access the password protected values as previously described. Key in the value for the specific model number from Table 3 and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next programmable option. NOTE: Proper operation is dependent on proper programming of this value. TABLE 2 - CHILLER SYS 1 AND SYS 2 MOTOR CURRENT = 100% FLA MODEL 200 VOLTS (-17) 230 VOLTS (-28) 460 VOLTS (-46) 575 VOLTS (-58) YEAS ENGR. DATA SYS 1 FLA SYS 2 FLA SYS 1 FLA SYS 2 FLA SYS 1 FLA SYS 2 FLA SYS 1 FLA SYS 2 FLA 135 5A2A2HL7A M5A2HL7A F5M5HL7A F5F5KL7A H6H6KL7A P6H5KN7A P7H6KN7A P7P7KN7A S7S7KN7A YORK INTERNATIONAL

65 FORM NM2 Shown below is an example of this display: S Y S T E M 1 C O N D T E M P F = % L O A D SYSTEM 2 COND TEMP If loading/unloading is selected utilizing slide valve %, the design condensing temperature (discharge pressure converted to temperature or CTP) at 100% load must be programmed for each system for the specific model of chiller that is utilized. To program SYSTEM 2 COND TEMP, access the password protected values as previously described. Key in the value for the specific model number from Table 3 and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next programmable option. NOTE: Proper operation is dependent on proper programming of this value. Shown below is an example of this display: S Y S T E M 2 C O N D T E M P F = % L O A D advance to the next programmable value. This is not password protected and can be programmed anytime the "PROGRAM" key is pressed. LOAD SHARE BASED ON? L O A D S H A R E B A S E D O N? 1 = S V %, 2 = % F L A 2 Selection of the LOAD SHARE BASED ON? determines whether loading/unloading (load sharing based on % FLA or % slide valve). Generally, each should operate satisfactory in most applications. The default method utilizes % FLA and is simpler and requires less programming. It is also less affected by ambient and system conditions. To select a method of load sharing, program a "1" for SV% (slide value %) or a "2" for % FLA (motor current) and press "ENTER". The mode of control will be entered into memory and the next programmable value will appear. This selection is not password protected and can be programmed at any time under the "PROGRAM" key. Additional details regarding selection of this program option are detailed starting on page 71. TABLE 3 - CHILLER SYS 1 AND SYS 2 DESIGN CONDENSING TEMP (CTP) MODEL FOR ALL VOLTAGES YEAS ENGR. DATA SYS 1 CTP SYS 2 CTP 135 5A2A2HL7A F F 145 5M5A2HL7A F F 155 5F5M5HL7A F F 165 5F5F5KL7A F F 185 5H6H6KL7A F F 195 5P6H5KN7A F F 197 5P7H6KN7A F F 215 5P7P7KN7A F F 225 5S7S7KN7A F F COMMUNICATIONS MODE C O M M U N I C A T I O N S M O D E 1 = I S N, 2 = R C C, 2 COMMUNICATIONS MODE allows the operator to select communications with a (1) ISN System or (2) an RCC (Remote Control Center Option). To program the COMMUNICATIONS MODE, key in the corresponding number and press the "ENTER" key. The programmed mode will be entered into memory and the display will "DEFAULT" VALUE PROGRAMMING IN THE PROGRAM MODE Programmable values may be individually programmed at start-up or anytime thereafter. For ease of programming, once the type of refrigerant is programmed in under the "PROGRAM" key, a password may be programmed in to automatically program default values into the micro. This will preset all programmable values under the "PROGRAM" key to values that will allow operation of the chiller under most operating conditions. This allows quick start-up programming for typical chilled water applications. To program the default values into the micro after the refrigerant type has been programmed, press the "PRO- GRAM" key, key in the numbers "6140", and press "ENTER". As the numbers are keyed in, s will appear: P R O G R A M M O D E When the "ENTER" key is pressed, the following message will appear: D E F A U L T S E T P O I N T S? 1 = Y E S, 0 = N O, 1 YORK INTERNATIONAL 65

66 Key in a "1" for YES, if default setpoints in Table 4 are desired. Key in a "0" for NO, if individually programmed values are desired. After the desired option is programmed, press ENTER to store the selection into memory. NOTE: Keep in mind that it is often easier to select Default Setpoints and then reprogram a few that require changing, versus programming each individual program option. display the message shown below before returning to the STATUS display. P R O G R A M O P T I O N S S E T T O D E F A U L T V A L U E S A list of the default values entered into memory, if this program option is selected, is shown in Table 4. If a "0" is selected, the display will return to the STATUS display. If a "1" is selected, the display will momentarily TABLE 4 - PROGRAM MODE DEFAULT VALUES REFRIGERANT TYPE PROGRAMMABLE OPTION DISCHARGE PRESSURE CUTOUT (R-22) DISCHARGE PRESSURE CUTOUT (R-134a) LOW AMBIENT TEMP CUTOUT PROGRAM 6140 DEFAULT N/A 399 PSIG 275 PSIG 0 F (LOW AMBIENT) 25 F (STANDARD AMBIENT) HIGH AMBIENT TEMP CUTOUT 130 F DISCHARGE PRESSURE UNLOAD (R-22) DISCHARGE PRESSURE UNLOAD (R-134a) 375 PSIG 255 PSIG AVERAGE CURRENT UNLOAD 105% ANTI RECYCLE TIME LEAVING CHILLED LIQUID TEMP CUTOUT SUCTION PRESSURE CUTOUT (R-22) SUCTION PRESSURE CUTOUT (R-134a) 600 SEC. 36 F (BRINE) 36 F (WATER) 44 PSIG (BRINE) 44 PSIG (WATER) 19 PSIG (BRINE) 19 PSIG (WATER) LAG COMPRESSOR START POINT 70% LAG COMPRESSOR DIFFERENTIAL OFF 50% TOTAL NUMBER OF FANS ON CHILLER FAN CONTROL DISCHARGE PRESSURE SET POINT (R-22) FAN CONTROL DISCHARGE PRESSURE SET POINT (R-134a) FAN ON/OFF PRESSURE DIFFERENTIAL SYSTEM 1 MOTOR CURRENT FLA SYSTEM 2 MOTOR CURRENT FLA N/A 230 PSIG 102 PSIG 50 PSIG LIQUID INJECTION TEMP LIMIT 180 F SYSTEM 1 FULL LOAD CONDENSER TEMPERATURE SYSTEM 2 FULL LOAD CONDENSER TEMPERATURE COMMUNICATIONS MODE LOAD SHARING MODE 2 N/A N/A N/A N/A N/A 66 YORK INTERNATIONAL

67 FORM NM2 "SETPOINT" KEYS SETPOINT KEYS #28164 FIG "SETPOINT" KEYS GENERAL The microprocessor utilizes leaving chilled liquid control to maintain chilled liquid temperature within the programmed CONTROL RANGE (CR). Regulating leaving chilled liquid temperature within the CR is accomplished through capacity control of the compressor s slide valve. A series of load and unload pulses are sent to the compressor slide valve to maintain LWT within a desired range. Attention is also provided by the micro to maximize efficiency and minimize compressor cycling. The control algorithm in the micro combines control zones and internal timers to maintain chilled liquid temperatures and minimize cycling of the two compressors. This method of control is suitable for both water and brine cooling. Control setpoints (CONTROL RANGE) are programmed into the panel to establish the desired range of leaving chilled operating temperatures. A description of the operation and programming follows. PROGRAMMING CHILLED LIQUID TEMP / RANGE Chilled Liquid/Temp Range CHILLED LIQUID TEMP / RANGE When the "CHILLED LIQUID TEMP / RANGE" key is pressed, one of the following messages will be displayed for 3 seconds: L O C A L W A T E R T E M P C O N T R O L R E M O T E W A T E R T E M P C O N T R O L This message will inform the user that the chiller is selected to be controlled by a LOCAL (Control Panel) Setpoint control or REMOTE (FAX 4500, Remote PWM Signal, or Remote Control Center) Setpoint control. Selection is made on the S1 Dip Switch on the Microprocessor Board (Page 50). Normally, unless a FAX 4500, Remote PWM Signal or Remote Control Center is connected to the Micropanel, the Local Mode will be selected. The display will then scroll to a second message which will display the desired CONTROL RANGE (CR) and the "TARGET" temperature. C R = T O F T A R G E T = F The CONTROL RANGE (CR) is the programmed variation in leaving chilled liquid temperature which is ac- YORK INTERNATIONAL 67

68 ceptable to the user for the system application. The example above has a programmed CR of F. The user s desired leaving chilled temperature ("TAR- GET") will be 44.0 F or the midpoint of the CR. This midpoint temperature will be referred to as the "TAR- GET" temperature in the following description. The LOW LIMIT WATER TEMPERATURE is the minimum user acceptable leaving water temperature as defined by the programmed CONTROL RANGE (CR). The LOW LIMIT WATER TEMP. must be programmed into the Micropanel to establish the low end of the CR. In the example above, 42.0 F is programmed. The HIGH LIMIT WATER TEMPERATURE is the maximum user acceptable leaving water temperature as defined by the programmed CONTROL RANGE (CR). In the example above, the HIGH LIMIT WATER TEM- PERATURE is programmed in the CR at 46.0 F. Refer to Fig. 23 to aid in understanding the relationship of the LOW LIMIT WATER TEMP. (LLWT), HIGH LIMIT WATER TEMP. (HLWT), CONTROL RANGE (CR) and TARGET Temp F 44.0 F 42.0 F FIG CONTROL RANGE To assure that the chilled liquid temperatures stay within the CONTROL RANGE (CR), The micro will attempt to control leaving chilled liquid temperature to an even tighter temperature band than the low and high limits of the CONTROL RANGE (CR). This temperature band is known as the NEUTRAL ZONE. When chilled liquid is in the NEUTRAL ZONE, the micro will only initiate loading/unloading pulses if temperature is rising or falling faster than rate control limits internal to the micro. As mentioned before, the user s desired leaving water temperature is known as the "TARGET" temperature and is a temperature, midpoint in the CONTROL RANGE. The "TARGET" is also midpoint in the NEU- TRAL ZONE. The NEUTRAL ZONE temperature band is not programmable but can be calculated as follows: Example: "TARGET" TEMP. CONTROL RANGE (CR) HIGH LIMIT WATER TEMP LOW LIMIT WATER TEMP Neutral = Target +/- HLWT - LLWT Zone 4 USER ACCEPTABLE LEAVING CHILLED LIQUID OPERATING RANGE From the example: Neutral = 44 F +/- 46 F - 42 F Zone 4 Neutral = 44 F +/- 1 F Zone In the example above, with a CR = 42.0 to 46.0 F, the "TARGET" temperature will be 44.0 F with a Neutral Zone of 44.0 F +/- 1 F. Refer to Fig. 24 to aid in understanding the relationship between the LOW LIMIT WATER TEMP., HIGH LIMIT WATER TEMP., "TAR- GET", CONTROL RANGE (CR), and NEUTRAL ZONE F 45.0 F 44.0 F 43.0 F 42.0 F TARGET TEMP. FIG NEUTRAL ZONE HIGH LIMIT WATER TEMP NEUTRAL ZONE (No Loading/Unloading Occurs) LOW LIMIT WATER TEMP CONTROL RANGE (CR) As mentioned previously, no loading or unloading will occur in the NEUTRAL ZONE unless internal non-programmable rate control is exceeded. Limited loading will occur in the temperature range between the top end of the NEUTRAL ZONE and the HIGH LIMIT WATER TEMP. (HLWT). Normal loading, dictated by internal timers will occur above the CONTROL RANGE (CR). Limited unloading will occur when temperature falls between the bottom of the NEUTRAL ZONE and the LOW LIMIT WATER TEMP. (LLWT). Normal unloading, dictated by internal timers will occur below the CON- TROL RANGE (CR). To program the CONTROL RANGE (CR), press the "CHILLED LIQUID TEMP. / RANGE" key. For 3 seconds, the display will show either that Local or Remote Water Temp. Control is selected. The display will then automatically scroll to the CONTROL RANGE (CR) and "TARGET" temperature with the cursor stopping at the first digit of the CONTROL RANGE (CR). Key in the Low Limit of the CONTROL RANGE (CR) that is acceptable in the system. See below: Low Limit Water Temperature C R = T O F T A R G E T = F The micro will accept a range of programmable values from F. To program setpoints below 38 F, Dip Switch S1, Switch #1 on the Microprocessor Board 68 YORK INTERNATIONAL

69 FORM NM2 must be properly programmed for Brine Cooling (see page 50). If the switch is incorrectly selected, when setpoints below 38 F are entered, as well as when unacceptable values are entered, the following message will be displayed: O U T O F R A N G E T R Y A G A I N! After the LOW LIMIT WATER TEMP. (LLWT) is keyed in, the cursor will automatically advance to the final entry which is the upper limit (HIGH LIMIT WATER TEMP.) of the CONTROL RANGE (CR). This value should be programmed for the highest leaving water temperature which is acceptable in the system application. Typically 4 F above the LLWT is acceptable. The micro will accept a value 1-5 F above the LLWT. 4 F above the LLWT is the default value. Key in the upper limit HIGH LIMIT WATER TEMP (HLWT) of the CR and press the "ENTER" key. After pressing the "ENTER" key, the display will continue to show the message until another key is pressed. See below: High Limit Water Temperature C R = T O F T A R G E T = F This display will automatically show the "TARGET" temperature which is the desired leaving chilled liquid temperature and the actual chilled liquid temperature the micro will attempt to control to. The "TARGET" temperature will always be the midpoint of the CONTROL RANGE (CR). C R = T O F T A R G E T = F Target Water Temperature NOTE: Failure to press the "ENTER" key will cause the newly programmed values to not be entered into memory. CAUTION: A Control Range (CR) selection that is too small for the application will result in compressor(s) cycling and hunting of the slide valve. If this situation occurs, leaving chilled liquid temperature may vary considerably. It is recommended that a CR of less than 3.0 F be avoided. Increase the CR as needed to reduce cycling and hunting. NOTE: Whenever reprogramming the CR, keep in mind that the desired leaving chilled liquid temperature, or "TARGET" will be the midpoint of the CR. COMPRESSOR LOADING AND UNLOADING The micro loads and unloads individual compressors by pulsing the slide valve solenoid which controls oil flow to the slide valve. The slide valve solenoid provides oil pressure assist to the port of the slide valve which either increases or decreases capacity. Whenever temperature is above the Neutral Zone, loading pulses will be applied to open the loading port on the control solenoid allowing oil pressure to move the slide valve to increase capacity. Every seconds, the micro will pulse the slide valve with a second pulse. The time between pulses will be a function of the temperature deviation from the "TARGET" chilled liquid temperature. The duration of the pulse will be a function of the deviation from "TARGET" chilled liquid temperature, rate of water temperature change, suction pressure, discharge pressure, and % load current. Pressure is a factor since the amount of slide valve movement for a given pulse is dependent on the discharge pressure. Motor current is a factor to assure the slide valve position changes do not cause the compressor to exceed the current limit unload point. For the first two and a half minutes of compressor operation, no loading will occur. Whenever temperature is below the Neutral Zone, unloading pulses will be sent to open the unloading port on the control solenoid to relieve oil pressure on the slide valve. This allows oil pressure to move the slide valve to decrease capacity. Every 6-70 seconds, the micro will pulse the slide valve with a second pulse. The duration and length of the pulse will be a function of the deviation from setpoint. The larger the deviation, the longer the pulse. Limited loading/unload may occur in the Neutral Zone, if internal software "rate" control limits regulating abrupt changes in leaving chilled liquid are exceeded. SEQUENCE OF CHILLER LOADING AND UNLOADING Three programmable options dictate the loading sequence of the two compressors. These options allow Load Sharing by the two compressors based on % FLA or Slide Valve %, selection of the Lag Compressor Start %, and selection of the Differential OFF %. The loading sequence of the two compressors is programmable to operate from either % FLA or % Slide Valve Position. Over much of the range of loading of the two compressors, the micro will attempt to load each compressor equally based on % FLA or % Slide Valve for efficiency purposes. This is accomplished by selecting the type of load sharing desired, based on the % of FLA Motor Current or by the % Slide Valve Position. The type of loading is programmable under the "PROGRAM" key by selecting a "1" for SV% (slide valve %) or "2" for % FLA (motor current) when the display showing "LOAD SHARE BASED ON?" is accessed. YORK INTERNATIONAL 69

70 Selection of the LAG COMPRESSOR START POINT % under the "PROGRAM" key, allows the user to select the loading point of the lead compressor at which the lag compressor starts. Once the lag compressor starts, equalized load sharing will begin. Selection of the DIFFERENTIAL OFF % determines the range of unloading over which load sharing will occur. Two Control Schemes may be selected. Load Sharing, programming of the start point %, and differential off % will first be discussed in CONTROL SCHEME 1 utilizing % FLA Motor Current and then in CONTROL SCHEME 2 utilizing % Slide Valve. Each one should be reviewed before a selection is made. Both control schemes should work well for most applications. For simplicity of programming to eliminate manual programming required in each of the two Control Schemes, the "DEFAULT" programming points (page 58) may be selected. This selects LOAD SHARING BASED ON % FLA as the control means for load sharing with a LAG COMPRESSOR START POINT % of 70% FLA. It also selects a LAG DIFFERENTIAL OFF % of 50%. These control points may be programmed individually under the "PROGRAM" key without selecting all "Default" values as mentioned on page 58. CONTROL SCHEME 1 Loading And Unloading Utilizing % FLA Control The LAG COMPRESSOR START POINT % (FLA), is programmable in the "PROGRAM" mode. By selecting a LAG COMPRESSOR START POINT % (FLA), the user is actually selecting the % FLA at which the lead compressor is allowed to load, before the lag compressor is brought on. This % is programmable from 40-99%. The micro will start the lead compressor whenever the chilled liquid temperature is above the High Limit of the CONTROL RANGE (CR) and the 3 minute "Start Timer" has timed out. The 3 minute "Start Timer" is the minimum amount of time that the compressor must remain off after a cycling shutdown (Anti-Recycle Timer Timed Out) or after power is first applied. Once started, the micro will pulse the slide valve to load the lead compressor to bring the chilled liquid within the Neutral Zone. If temperature is not brought down to within the Neutral Zone, the lag compressor will be brought on by the micro after the lead compressor loads up to the programmed LAG COMPRESSOR START POINT % as determined and programmed by the user. If due to system conditions, the lead compressor does not reach the programmed %, even though the lead compressor may be fully loaded, the lag compressor will start regardless of the programmed Start % after 5 minutes of operation. This will occur whenever the lead compressor cannot bring the LWT to within 2.0 F of the high end of the CONTROL RANGE (CR). Once the lag compressor is started, equalized loading and unloading of the two compressors will occur based on % FLA. The 5 minute default for lag compressor start assures that the lag compressor will start and load in situations where the lead compressor % FLA does not reach the programmed LAG COMPRESSOR START POINT %. These situations may be common because as ambients drop, actual % FLA at full load will drop at 100% slide valve. Actual operating % FLA for a compressor that is fully loaded may often be 65-85% of the motor FLA at ambients below 95 F. As mentioned above, after the lead compressor starts and loads up to the programmed 40-99%, if temperature is still above the CONTROL RANGE (CR), the lag compressor will come on. It will then be brought up to a % FLA equal to the lead compressor provided demand dictates. At this point, the loading of both compressors will be adjusted up or down to maintain capacity and equalize loading. NOTE: Under most operating conditions, viewing % FLA of each compressor will show a difference in the FLA of each compressor which at times may be significant. This condition will exist even though equalized loading/unloading should be observed. This is due to the micro constantly pulsing slide valves of each compressor to control temperature and differences in operating conditions of the two compressors, such as discharge pressure which causes each compressor s slide valve to move a different amount with a pulse of a specific duration. Other system pressures and mechanical tolerances within compressors will also contribute to differences. Regardless of the differences in % FLA, the micro will still assure that leaving chilled liquid temperature is properly controlled. Also, in some cases, the micro will not be programmed to attempt to control equalized unloading over the entire loading range which will affect the unloading sequence slightly. Refer to page 72, "Selecting The LAG COM- PRESSOR DIFFERENTIAL OFF %" for details. Approximate loading time for each compressor on a hot water start is about 5 minutes per compressor at worst case conditions. If the load drops, both compressors will each unload equally to a point as determined by the LAG COMPRESSOR DIFFERENTIAL OFF %. When further capacity reduction is required, the lag compressor will continue to unload, and shutdown while the lead compressor maintains its % FLA loading point. When fully 70 YORK INTERNATIONAL

71 FORM NM2 unloaded, the lag compressor will shut down under 2 conditions: 1. When chilled liquid temperature drops below the Neutral Zone. 2. When chilled liquid temperature drops below the "TARGET" temperature and the rate of change exceeds the internally programmed rate limits. The micro may also shut down the lag compressor before it is totally unloaded to avoid cut-out of the entire chiller on a Low Water Temp. Fault. This will occur under 2 conditions: 1. The leaving chilled liquid temperature falls below the low end of the CONTROL RANGE (CR) for 37 seconds. 2. The leaving chilled liquid temperature drops below the low end of the CONTROL RANGE (CR) minus CR/4. Individual compressor loading is computed by the micro based on counting load/unload pulses. The micro bases loading on a 50 pulse scale. After 50 loading pulses, from total unload, the micro assumes full load at "50" on the scale of 0-50 pulses. Unload pulses subtract from the numerical value on the scale, whatever it may be. "0" is fully unloaded on the 0-50 pulse scale. As loading and unloading pulses are sent, the micro continues to keep track by adding and subtracting pulses on the 0-50 pulse scale. After the lag compressor is shut down, the lead compressor loading will be adjusted up or down to control temperature within the Neutral Zone. As load drops, the micro will keep track of the load pulses sent to the lead compressor. At minimum loading, the lead compressor will shut down when temperature drops below the low limit of the CONTROL RANGE (CR). The lead compressor may also shut down while partially loaded to avoid cut-out on a Low Water Temperature Fault, if temperature drops 2 degrees below the low limit of the CONTROL RANGE (CR) or if temperature drops CR/2 below the low limit of the CONTROL RANGE (CR). Selecting The LOAD SHARE BASED ON? Selection of the LOAD SHARE BASED ON? is accomplished under the "PROGRAM" key. To control from % FLA motor current, key in a "2" as shown below and press the "ENTER" key. L O A D S H A R E B A S E D O N? 1 = S V %, 2 = % F L A 2 This programmable display is not password protected. Selecting The Lag Compressor Start Point % Selection of the LAG COMPRESSOR START POINT % under the "PROGRAM" key primarily allows the user to either allow the lead compressor to fully load before the lag compressor is started, or start the lag compressor is fully loaded. Key in a start point % and press the "ENTER" key. A sample display is shown below: L A G C O M P R E S S O R S T A R T P O I N T 7 0 % This programmable display is not password protected. Selecting a LAG COMPRESSOR START POINT % of 99% assures that the lead compressor is fully loaded before the lag compressor is brought on. If very low loads are expected, less compressor cycling will be noted by selecting a high slide valve percentage. 99% would be recommended for absolute minimum cycling. If due to system conditions, the lead compressor does not reach the programmed %, even though the lead compressor is fully loaded, the lag compressor will start regardless of the programmed % after 5 minutes of operation whenever the lead compressor cannot bring the leaving chilled liquid within 2.0 F of the high end of the CONTROL RANGE (CR). This assures that the lag compressor starts if demand is present, regardless of the program points. Once the lag compressor is started, equalized loading and unloading will occur as previously described. This assures that the chiller will fully load and maintain chilled liquid temperature. Selecting a LAG COMPRESSOR START POINT % less than 99% increases the efficiency of the chiller. At lower percentages, the lead compressor is loaded to the programmed % and the lag compressor is started and brought up to a % motor FLA equal to the lead compressor as load permits. At this point the loading of both compressors is adjusted up or down to maintain capacity and equalize loading. Running both compressors partially loaded makes more efficient use of the evaporator bundle than running one compressor fully loaded with the other idle. This assures that the entire evaporator is being utilized and maximum chiller efficiency is achieved. However, keep in mind that as more capacity is required, the lag compressor will start regardless of the programmed % and equalized loading at part load will still be achieved, even with a programmed % of 99%. If a LAG COMPRESSOR START POINT % of less than 99% is desired, a value of 70% is recommended. This will typically assure that the lag compressor will start before the lead compressor is fully loaded in most operating conditions. Selecting The LAG COMPRESSOR DIFFERENTIAL OFF % Selection of the LAG COMPRESSOR DIFFERENTIAL OFF % under the "PROGRAM" key allows the operator to select the range over which the lead and lag compressor load shares equally. This affects the loading se- YORK INTERNATIONAL 71

72 quence at low loads. Once the lag compressor is brought on and loads up to a % FLA equal to the lead compressor, if demand allows, Load sharing of the compressors will begin. Load sharing will continue until loading of the compressors drops to the programmed differential % below the LAG COMPRESSOR START POINT %. For example: If a LAG COMPRESSOR START POINT of 70% is selected, and a LAG COMPRESSOR DIFFER- ENTIAL OFF % of 50% is selected, the lead and lag compressor will both load share until the % FLA of the lead compressor drops to 20% (70% - 50% = 20%). At this point, the micro will unload only the lag compressor until it reaches a point at which the micro determines it is fully unloaded and the load does not require its continued operation. The micro will then cycle the lag compressor off. It will also cycle off as described previously, if the micro determines that chilled liquid temperature is dropping too low. The larger the differential programmed, the more efficient the use of the evaporator. For efficiency purposes, 50% is recommended. Cycling of the lag compressor will also be minimized since equalized unloading operates for a longer period of the loading/unloading scheme. A small % differential will increase cycling and lower efficiency slightly. For example: If 10% LAG COMPRES- SOR DIFFERENTIAL OFF % is selected with a LAG COMPRESSOR START POINT % of 70%, the lag compressor will start when the lead % FLA reaches 70%. The lag loading will be brought up to equalize the lead of 70% if demand requires. Both compressors will increase in loading proportionately as demand increases. When the load drops, both compressors will unload to 60% (70% - 10% = 60%). At this point, only the lag compressor will be unloaded as demand decreases. It will unload to a point at which the micro determines it is fully unloaded. If load does not require its continued operation, the compressor will cycle off. A minimum % FLA point is built into the micro to only allow load sharing to operate to a minimum of 20% FLA of the lead compressor. Therefore, the LAG COMPRES- SOR START % MINUS THE LAG COMPRESSOR DIF- FERENTIAL OFF % cannot be less than 20% or an OUT OF RANGE message will appear. To program the LAG COMPRESSOR DIFFERENTIAL OFF % under the "PROGRAM" key, key in the desired value and press the "ENTER" key. The new value will be entered into memory. This value is not password protected and can be programmed anytime the "PRO- GRAM" key is pressed. Shown below is an example of this display: L A G C O M P R E S S O R D I F F E R E N T I A L O F F 5 0 % The micro will accept a range of programmable values between 0-50% for this operating control, provided the LAG COMPRESSOR START POINT % minus the LAG COMPRESSOR DIFFERENTIAL OFF % does not equal less than 20%. CONTROL SCHEME 2 Loading And Unloading Utilizing % FLA And Condensing Temperature To Predict Slide Valve Position This control method uses a slightly more complex scheme to control loading/unloading and requires slightly more programming. This scheme was derived from a computer model and actual tests under controlled conditions to plot slide valve position versus motor current and condensing temperature (CTP). The chiller sensors involved in the control scheme are the motor current C.T. s and discharge pressure transducers. Actual condensing temperature is derived from system discharge pressure. Slide valve position calculation requires that the micro be programmed to know a specific chiller s FLA at 100% load at design conditions. This is required for each individual refrigerant system. The system Motor Current = 100% FLA value will vary from chiller to chiller and should be programmed according to the model number and voltage from Table 5. Access the password protected values and key in the current that equals 100% FLA and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next programmable value. Repeat for the other system. The displays for each system programmable value will appear as shown below: S Y S T E M M O T O R C U R R A M P S = % F L A S Y S T E M 2 M O T O R C U R R A M P S = % F L A To compute slide valve position, the DESIGN COND TEMP. must be entered under the "PROGRAM" key. The Condensing Temperature is entered as F / C equating to 100% load at design conditions. The temperature to be programmed will vary from chiller to chiller and should be programmed according to Table 6. NOTE: It will be required to program a value for each system. The allowable range of DESIGN COND TEMP. is F ( C) with the default set for 125 F (51.7 C). 72 YORK INTERNATIONAL

73 FORM NM2 TABLE 5 - CHILLER SYS 1 AND SYS 2 MOTOR CURRENT = 100% FLA MODEL 200 VOLTS (-17) 230 VOLTS (-28) 460 VOLTS (-46) 575 VOLTS (-58) YEAS ENGR. DATA SYS 1 FLA SYS 2 FLA SYS 1 FLA SYS 2 FLA SYS 1 FLA SYS 2 FLA SYS 1 FLA SYS 2 FLA 135 5A2A2HL7A M5A2HL7A F5M5HL7A F5F5KL7A H6H6KL7A P6H5KN7A P7H6KN7A P7P7KN7A S7S7KN7A The DESIGN SYSTEM COND TEMP. is password protected under the "PROGRAM" key. The displays will appear as follows: S Y S T E M 1 C O N D T E M P F = % L O A D TABLE 6 - CHILLER SYS 1 AND SYS 2 DESIGN CONDENSING TEMP (CTP) MODEL FOR ALL VOLTAGES YEAS ENGR. DATA SYS 1 CTP SYS 2 CTP 135 5A2A2HL7A F F 145 5M5A2HL7A F F 155 5F5M5HL7A F F 165 5F5F5KL7A F F 185 5H6H6KL7A F F 195 5P6H5KN7A F F 197 5P7H6KN7A F F 215 5P7P7KN7A F F 225 5S7S7KN7A F F Program the design temperature for the respective system and press "ENTER". Repeat for the other system. This value is not password protected and can be programmed anytime the "PROGRAM" key is pressed. The LAG COMPRESSOR START POINT % is programmable in the "PROGRAM" mode. By selecting a LAG COMPRESSOR START %, the user is actually selecting the % slide valve at which the lead compressor is allowed to load, before the lag compressor is brought on. This % is programmable from 40-99%. NOTE: This is in contrast to Scheme 1 where LAG COMPRESSOR START % relates to % FLA. The micro will start the lead compressor whenever the chilled liquid temperature is above the High Limit of the Control Range (CR) and the 3 minute "Start Timer" has timed out. The 3 minute "Start Timer" is the minimum amount of time that the compressor must remain off after a cycling shutdown (Anti-Recycle Timer Timed Out) or after power is first applied. Once started, the micro will pulse the slide valve to load the lead compressor to bring the chilled liquid temperature within the NEUTRAL ZONE. If temperature is not brought down to within the "Neutral Zone", the lag compressor will be brought on by the micro after the lead compressor loads up to the programmed LAG COMPRESSOR START POINT % as determined and programmed by the user. If due to system conditions, the lead compressor does not reach the programmed %, even though the lead compressor may be fully loaded, the lag compressor will start regardless of the programmed Start % after 5 minutes of operation. This will occur whenever the lead compressor cannot bring the LWT to within 2.0 F of the high end of the CONTROL RANGE (CR). Once the lag compressor is started, equalized loading and unloading of the two compressors will occur based on slide valve %. The 5 minute default for lag compressor start assures that the lag compressor will start and load in situations where error is introduced into the micro calculation for computing slide valve %. These situations may occur due to tolerances in discharge pressure transducers, ambients, dirt on coils, subcooling, superheat, etc. As mentioned above, after the lead compressor starts and loads up to the programmed 40-99%, if temperature is still above the CONTROL RANGE (CR), the lag compressor will come on. It will then be brought up to a % slide valve equal to the lead compressor provided demand dictates. At this point, the loading of both compressors will be adjusted up or down to maintain capacity and equalize loading. NOTE: Under most operating conditions, viewing % slide valve of each compressor will show a difference in the % slide valve of each compressor which at times may be significant. This condition will exist even though equalized loading / unloading should be observed. This is due to the micro constantly pulsing slide valves of each compressor to YORK INTERNATIONAL 73

74 control temperature and differences in operating conditions of the two compressors, such as discharge pressure which causes each compressor s slide valve to move a different amount with a pulse of a specific duration. Other factors such as tolerances in discharge pressure transducers and mechanical tolerances within compressors will also contribute to differences. Regardless of the differences in % slide valve, the micro will still assure that leaving chilled liquid temperature is properly controlled. Also, in some cases, the micro will not be programmed to attempt to control equalized unloading over the entire loading range which will affect the unloading sequence slightly. Refer to page 72 "Selecting The LAG COM- PRESSOR DIFFERENTIAL OFF %" for details. Approximate loading time for each compressor on a hot water start is about 5 minutes per compressor at worst case conditions. If the load drops, both compressors will each unload equally to a point as determined by the LAG COMPRESSOR DIFFERENTIAL OFF %. When further capacity reduction is required, the lag compressor will continue to unload, and shutdown while the lead compressor maintains its % slide valve loading point. When fully unloaded, the lag compressor will shut down under 2 conditions: 1. When chilled liquid temperature drops below the Neutral Zone. 2. When chilled liquid temperature drops below the "TARGET" temperature and the rate of change exceeds the internally programmed rate limits. The micro may also shut down the lag compressor before it is totally unloaded to avoid cut-out of the entire chiller on a Low Water Temp Fault. This will occur under 2 conditions: 1. The leaving chilled liquid temperature falls below the low end of the CONTROL RANGE (CR) for 37 seconds. 2. The leaving chilled liquid temperature drops below the low end of the CONTROL RANGE (CR) minus CR/4. Individual compressor loading is also computed by the micro based on counting load/unload pulses. The micro bases loading on a 50 pulse scale, after 50 loading pulses from total unload, the micro assumes full load at "50" on the scale of 0-50 pulses. Unload pulses subtract from the numerical value on the scale, whatever it may be. "0" is fully unloaded on the 0-50 pulse scale. As loading and unloading pulses are sent, the micro continues to keep track by adding and subtracting pulses on the 0-50 pulse scale. After the lag compressor is shut down, the lead compressor loading will be adjusted up or down to control temperature within the Neutral Zone. As load drops, the micro will keep track of the load pulses sent to the lead compressor. At minimum loading, the lead compressor will shut down when temperature drops below the low limit of the CONTROL RANGE (CR). The lead compressor may also shut down while partially loaded to avoid cut-out on a Low Water Temperature Fault, if temperature drops 2 degrees below the low limit of the CONTROL RANGE (CR) or if temperature drops CR/2 below the low limit of the CONTROL RANGE (CR). Selecting The LOAD SHARE BASED ON? Selection of the LOAD SHARE BASED ON? can be made under the "PROGRAM" key. To control from slide valve %, key in a "1" as shown below and press the "ENTER" key. L O A D S H A R E B A S E D O N? 1 = S V %, 2 = % F L A 1 This programmable display is not password protected. Selecting The Lag Compressor Start Point % Selection of the LAG COMPRESSOR START % under the "PROGRAM" key primarily allows the user to either allow the lead compressor to fully load before the lag compressor is started, or start the lag compressor fully loaded. Key in a start % and press "ENTER" key. A sample display is shown below: L A G C O M P R E S S O R S T A R T P O I N T 7 0 % This programmable display is not password protected. Selecting a LAG COMPRESSOR START % of 99% assures that the lead compressor is fully loaded before the lag compressor is brought on. If very low loads are expected, less compressor cycling will be noted by selecting a high slide valve percentage. 99% would be recommended for absolute minimum cycling. If due to system conditions, the lead compressor does not reach the programmed %, even though the lead compressor is fully loaded, the lag compressor will start regardless of the programmed % after 5 minutes of operation. This will occur whenever the lead compressor cannot bring the leaving chilled liquid within 2.0 F of the high end of the CONTROL RANGE (CR). Once the lag compressor is started, equalized loading and unloading will occur as previously described. This assures that the chiller will fully load and maintain chilled liquid temperature. Selecting a LAG COMPRESSOR START % less than 99% increases the efficiency of the chiller. At lower 74 YORK INTERNATIONAL

75 FORM NM2 percentages, the lead compressor is loaded to the programmed % and the lag compressor is started and brought up to a % slide valve equal to the lead compressor. At this point the loading of both compressors is adjusted up or down to maintain capacity and equalize loading. Running both compressors partially loaded makes more efficient use of the evaporator bundle than running one compressor fully loaded with the other idle. This assures that the entire evaporator is being utilized and maximum chiller efficiency is achieved. However, keep in mind that as more capacity is required, the lag compressor will start regardless of the programmed % and equalized loading at part load will still be achieved, even with a programmed % of 99%. If a LAG COMPRESSOR START % of less than 99% is desired, a value of 70% is recommended. This will typically assure that the lag compressor will start before the lead compressor is fully loaded in most operating conditions. Selecting The LAG COMPRESSOR DIFFERENTIAL OFF % Selection of the LAG COMPRESSOR DIFFERENTIAL OFF % under the "PROGRAM" key allows the operator to select the range over which the lead and lag compressor load shares equally. This affects the loading sequence at low loads. Once the lag compressor is brought on and loads up to a % Slide Valve equal to the lead compressor, load sharing of the compressor will begin. Load sharing will continue until loading of the compressor drops to the programmed differential % below the LAG COMPRESSOR START POINT %. For example: If a LAG COMPRESSOR START POINT of 70% is selected, and a LAG COMPRESSOR DIF- FERENTIAL OFF % of 50% is selected, the lead and lag compressor will both load share until the % Slide Valve of the lead compressor drops to 20% (70% - 50% = 20%). At this point, the micro will unload only the lag compressor until it reaches a point at which the micro determines it is fully unloaded and the load does not require its continued operation. The micro will then cycle the lag compressor off. It will also cycle off as described previously, if the micro determines that chilled liquid temperature is dropping too low. A small % differential will increase cycling and lower efficiency slightly. For example: If 10% LAG COM- PRESSOR DIFFERENTIAL OFF % is selected with a LAG COMPRESSOR START POINT % of 70%, the lag compressor will start when the lead % FLA reaches 70%. The lag loading will be brought up to equalize the lead of 70% if demand requires. Both compressors will increase in loading proportionately as demand increases. When the load drops, both compressors will unload to 60% (70% - 10% = 60%). At this point, only the lag compressor will be unloaded as demand decreases. It will unload to a point at which the micro determines it is fully unloaded. If load does not require its continued operation, the compressor will cycle off. A minimum % FLA point is built into the micro to only allow load sharing to operate to a minimum of 20% Slide Valve % of the lead compressor. Therefore, the LAG COMPRESSOR START % MINUS THE LAG COM- PRESSOR DIFFERENTIAL OFF % cannot be less than 20% or an OUT OF RANGE message will appear. To program the LAG COMPRESSOR DIFFERENTIAL OFF % under the "PROGRAM" key, key in the desired value and press the "ENTER" key. The new value will be entered into memory. This value is not password protected and can be programmed anytime the "PRO- GRAM" key is pressed. Shown below is an example of the display: L A G C O M P R E S S O R D I F F E R E N T I A L O F F 5 0 % To program the LAG COMPRESSOR DIFFERENTIAL OFF % under the "PROGRAM" key, key in the desired value and press the "ENTER" key. The new value will be entered into memory and the display will advance to the next user programmable value. This value is not password protected and can be programmed anytime the "PROGRAM" key is pressed. The micro will accept a range of programmable values between 0-50% for this operating control, provided the LAG COMPRESSOR START POINT % minus the LAG COMPRESSOR DIFFERENTIAL OFF % does not equal less than 20%. The larger the differential programmed, the more efficient the use of the evaporator. For efficiency purposes, 50% is recommended. Cycling of the lag compressor will also be minimized since equalized unloading operates for a longer period of the loading/unloading scheme. YORK INTERNATIONAL 75

76 SAFETIES GENERAL There are both System Safeties and Total Chiller Safeties programmed into the micropanel. System Safeties may either be Manual Reset or Anticipation Type. Chiller safeties will be Automatic Reset Type. These safeties protect the chiller from damage anytime a safety threshold is exceeded by either shutting the system(s) down or by altering system loading. Continuous monitoring by the microprocessor assures that instantaneous reactions result. A status display message will indicate when a system(s) or the entire chiller is shut down due to a fault or when Anticipation safeties are operating. An explanation of these safeties follows. MANUAL RESET SAFETIES A Manual Reset Safety will shut the affected system down whenever the safety threshold is exceeded. Automatic restart will occur after the first 2 shutdowns when the anti-recycle timer times out, if temperature demand exists. After any combination of 3 Manual Reset Safeties in a 90 minute time period, the affected system will shut down and lock out on a FAULT. After a system has shut down 3 times and locked out, a fault display indicating the last system fault will appear on the STATUS display message. This is accessible by pressing the "STATUS" key. NOTE: The High Motor Current Safety is a unique safety that will lock out a system after only a single fault. To reset a locked out system, turn the affected system switch on the Microprocessor Board (Page 55) to the OFF position. CAUTION: Before returning a locked out system to service, a thorough investigation of the cause of the fault should be made. Failure to repair the cause of the fault while manually allowing repetitive restarts may cause further expensive damage to the system. Each of the Manual Reset Safeties will be discussed in detail below. Discharge Pressure Safety The Discharge Pressure Safety assures that the system pressure does not exceed safe working limits which could open a relief valve or other pressure relief device causing refrigerant loss. This safety is a back-up for the mechanical High Pressure Cut-out in the system. The Discharge Pressure Safety is bypassed for the first 5 seconds of operation. After 5 seconds, if the cut-out point is exceeded for 3 seconds, the system will shut down. The Discharge Pressure Safety Cut-out is programmable by the user (Page 81). An example of a discharge pressure fault display message is shown below: S Y S 1 H I G H D S C H P R E S S Y S 2 H I G H D S C H P R E S Oil Pressure Safety The Oil Pressure Safety assures that the compressor s mechanical components receive proper lubrication. The micro begins monitoring compressor oil pressure after 3 minutes of operation. If oil pressure increases above (pressure drops) the differential oil pressure cut-out threshold for more than 3 seconds, the system will shut down. Under typical operation, the oil pressure display will normally read less than 45 PSID. As oil pressure drops, the differential pressure on the display will increase, which means that oil pressure is moving closer to suction pressure. Optimum oil pressure will approach 0 PSID on the micropanel display. After 3 minutes of operation, oil pressure must be less than 45 PSID (R22) or 40 PSID (R134a) for as long as the compressor continues to run. If the required oil pressure limits are not met, the system will shut down. The micro computes "differential oil pressure" by measuring discharge pressure and subtracting oil pressure returning to the compressor (Discharge - Oil = Oil PSID). An example of an oil pressure fault display follows: S Y S 1 H I G H O I L D I F F S Y S 2 H I G H O I L D I F F Suction Pressure Safety The Suction Pressure Safety assures that the system is not allowed to operate under low refrigerant conditions or due to a problem which will not allow proper refrigerant flow. When a compressor starts, the micro ignores suction pressure until a pumpdown is completed (pumpdown to cut-out or 30 sec., whichever comes first.). After pumpdown, the micro begins monitoring the suction 76 YORK INTERNATIONAL

77 FORM NM2 pressure and continues to do so as long as the compressor runs. For operation periods in the first 270 seconds, it is permissible for the suction pressure to be less than the programmed cut-out, but must be greater than: Run Time x SPCO = Cut-out 100 Programmed Example: Run time = 60 seconds Programmed Cut-out = 44 PSIG x 44 = 13.2 PSIG A close examination of the formula indicates the suction pressure cut-out increases with time for the first 270 seconds after the safety becomes active. After 270 seconds, the suction pressure must be greater than the cut-out. A transient timer is built into the software to assure that short term fluctuations in suction pressure due to fan cycling, loading, etc. do not cause nuisance trips on low suction pressure. After 270 seconds of operation, the transient timer is activated. If suction pressure drops below the cut-out point, the 90 second transient timer begins timing and the suction pressure must be greater than: 10 + (90 - transient time left) x SPCO 100 Example: Transient timer has been in effect for 30 sec. (60 sec. left) Programmed cut-out = 44 PSIG 10 + (90-60) x 44 = 17.6 PSIG 100 The longer the transient timer times, the higher the suction pressure must be. As long as the suction pressure stays above the cut-out point as dictated by the formula, the system will stay on line. 90 seconds after the transient timer starts, suction pressure must exceed the programmed cut-out. After the pressure exceeds SPCO + 5 PSIG, the transient timer will reset. Should the pressure not reach SPCO + 5 PSIG which resets the transient timer, but still remain above the cut-out, the compressor will continue to run until suction pressure drops below the cutout. At this time it will immediately shut down on a low pressure fault. The Suction Pressure Safety Cut-out is programmable by the user (Page 61). An example of a suction pressure fault message is shown below: S Y S 1 L O W S U C T I O N S Y S 2 L O W S U C T I O N High Motor Current Safety The High Motor Current Safety shuts a system down and locks it out after only a single occurrence of a rise in average motor current above the cut-out point. The safety attempts to provide motor protection should an overload occur due to a system or external problem. The micro monitors motor current with 3 C.T. s per motor, one on each phase T1, T2 and T3 in both WYE-Delta or Across-the-Line starters. High current conditions may result from power problems, contactor problems, wiring problems, refrigerant overcharge, very high chilled liquid temperatures, very high ambients, or situations that cause high discharge pressures. The micro begins monitoring "average" motor current after 5 seconds of compressor operation on chillers with ACROSS-THE-LINE start and after 20 seconds on chillers with WYE-DELTA starters. Between 5-7 seconds of run time (ACROSS-THE-LINE) or seconds (WYE-DELTA) "average" motor current must be less than 120% FLA, or the micro will shut the compressor down. After 7 seconds of operation (ACROSS-THE- LINE) or 22 seconds (WYE-DELTA), "average" motor current must be less than 115% FLA as long as the compressor continues to run. Anytime these current thresholds are exceeded for 3 seconds, the system will shut down. NOTE: Do not confuse FLA and RLA. FLA (full load amps) is approximately 1.2 x RLA. RLA (running load amps) specified on the motor / chiller nameplate is typical current demand under rated operating conditions in a fully loaded system. Therefore, do not expect to always see 100% FLA when the system is fully loaded. In a fully loaded condition, motor currents may often run 65-85% FLA. An example of the high current fault display message is shown below: S Y S 1 H I G H M T R C U R R S Y S 2 H I G H M T R C U R R Phase Rotation Safety The Phase Rotation Safety assures that the compressor rotates in the proper direction eliminating the possibility of damage to the compressor. The micro will shut the compressor down after 4 seconds of operation whenever the phasing of the incoming power wiring is incorrect. Anytime this fault occurs, the solution is to switch any two of the three incoming power wires. YORK INTERNATIONAL 77

78 An example of the Phase Rotation Fault message is shown below: S Y S 1 P H A S E R O T A T I O N S Y S 2 P H A S E R O T A T I O N High Discharge Temperature Safety This safety assures that the compressor s screws do not overheat and expand causing them to be damaged. The compressor will not start or will shut down in the first 5 seconds of operation if the discharge temperature exceeds 225 F. After 5 seconds of operation, a warning message will be displayed if discharge temperature exceeds 225 F. The compressor will shut down if the discharge temperature exceeds 230 F. This safety operates in conjunction with the Oil Pressure Safety to assure proper oiling is taking place. If oiling is lost for any reason, the oil seal between the two screws will be lost and the compression ratio will drop. The loss in compression ratio will cause the discharge temperature to rise. An example of the High Discharge Temperature warning and fault message is shown below: S Y S 1 H I G H D S C H T E M P S Y S 2 H I G H D S C H T E M P Low Motor Current Safety This safety protects against system problems that cause low motor current. These problems could result in motor overheating, compressor failure, and system malfunction. Shown below is the display relating to this safety. Actual current as well as MP (Motor Protector) and HP (High Pressure Cut-out) are related to this safety. A Motor Overload Relay (OL) will also cause a low current fault. S Y S 1 L O W C U R R / M P / H P S Y S 2 L O W C U R R / M P / H P Low "average" motor current may result from running with low or no refrigerant. This safety protects against gross refrigerant problems until the low pressure bypass is deactivated by the micro. Low current may also be due to contactor or power problems or a compressor that is not pumping due to a mechanical malfunction. The micro monitors motor current with 3 C.T. s per motor, one on each phase T1, T2 and T3 in both Wye-Delta or Across-the Line starters. The micro begins monitoring "average" motor current after 5 seconds of compressor operation on chillers with ACROSS-THE-LINE start and after 20 seconds on chillers with WYE-DELTA starters. After 5 seconds of operation (ACROSS-THE-LINE) or 20 seconds (WYE- DELTA), "average" motor current must be greater than 5% (ambient 25 F), 10% (ambient F), or 15% (ambient >45 F) FLA but less than 115% FLA as long as the compressor continues to run. Anytime these current thresholds are exceeded for 3 seconds, the system will shut down. NOTE: Do not confuse FLA and RLA. FLA (full load amps) is approximately 1.2 x RLA. RLA (running load amps) specified on the motor / chiller nameplate, is typical current demand under rated operating conditions in a fully loaded system. Therefore, do not expect to see 100% FLA when the system is fully loaded. In a fully loaded condition, expect motor currents to run 65-85% FLA. Six internal sensors are built into the motor (3 on each end). These sensors are wired into the Motor Protector Module located inside the Motor Terminal Box. As the windings heat and cool, the resistance of the motor temperature sensors will change. If the windings overheat, the change in resistance in the sensors will be sensed by the Motor Protector Module. The module will open its MP contacts breaking the 115VAC fed to the 1CR (Sys 1) or 2CR (Sys 2) control relay.when a control relay is de-energized, power is removed from the compressor contact or which shuts the compressor off. When the motor contactor de-energizes, motor current falls to zero. The low motor current is sensed by the microprocessor and the system is shut down. Auto-restart will be permitted after shutdown, when the motor sensors cool and the MP contacts close. A fault lock-out will result if safety thresholds are exceeded three times in a 90 minute period. Each compressor is protected by an External Motor Overload (OL) Relay responsive to motor current. When the overload relay senses single phase operation, locked motor current in excess of 10 seconds, or sustained current overloads in excess of 140% of RLA, the device will trip. This opens the 1 OL (Sys 1) or 2 OL (Sys 2) contacts which de-energizes 1CR (Sys 1) or 2CR (Sys 2) control relay. When a control relay de-energizes, power is removed from the compressor contactors which shuts the compressor off. When the motor contactor de-energizes, motor current falls to zero. The low motor current is sensed by the microprocessor and the system is shut down. 78 YORK INTERNATIONAL

79 FORM NM2 The OL relay setting should never be altered. If for some reason the Overload Relay is replaced, the following procedure is used for set-up. A/L Start: C.T s sense total compressor current so OL Relay Dial Setting = (1.1 x RLA) 350 WYE-Delta Start: C.T. s sense 58% of total compressor current so OL Relay Dial Setting = (1.1 x 0.58 x RLA) 350 Anytime the External Motor Overload Relay trips, a manual reset of the device is required to restart the compressor. After the first fault, the micro will try two more restarts, but with the External Motor Overload Relay tripped, no restart can occur. The micro will then lock out the system. In addition to manually resetting the External Motor Overload Relay, the fault will also require reset by turning the system switch of problem system off. Assure that the cause of the fault is determined before returning the system to service. The HP (High Pressure) Cut-out will also cause the low current safety to activate. If discharge pressure exceeds 405 PSIG (HP Cut-out), the cut-out will open. When the cut-out opens, 115VAC power will be removed from the Motor Protector Module. When power is removed from the module, its MP contacts will open, breaking the 115VAC fed to the 1CR (Sys 1) or 2CR (Sys 2) control relay. When a control relay is de-energized, power is removed from the compressor contactors which shuts the compressor off. When the motor contactor de-energizes, motor current falls to zero. The low motor current is sensed by the microprocessor and the system is shut down. Auto-restart will be permitted after shutdown, when discharge pressure drops below 330 PSIG and the HP contacts close. A fault lock-out will result if safety thresholds are exceeded three times in a 90 minute period. Motor Current Unbalance Safety The Motor Current Unbalance Safety assures that current balance between each of the three phases is within an acceptable limit. This provided further motor protection by preventing operation which could overheat one winding causing damage to the motor. It also provides an early warning of problems such as contactor contact wear, loose power wiring connections, and voltage problems in building power sources. This safety is an alternative and an enhancement to the internal thermal protection already provided by the motor protector. After 1 second of operation, the current of any phase must be within + or - 40% of the average current of the three phases. Exceeding these limits for greater than 3 seconds will cause the compressor to shut down. An example of the Motor Current Unbalance Fault message is shown below: S Y S 1 M T R C U R R U N B A L S Y S 2 M T R C U R R U N B A L High Oil Temperature Safety This safety assures that oil temperature does not exceed a safe operating temperature due to a system problem in the oil cooling circuit which could cause damage to the compressor. Typical oil temperature during normal operation will be approximately F. For the first 2 minutes of operation, the oil temperature safety is bypassed. After 2 minutes of operation, if the oil temperature is above 225 F for more than 3 seconds, the compressor will shut down. An example of the High Oil Temp fault message is shown below: S Y S 1 S Y S 2 AUTOMATIC RESET SAFETIES H I G H O I L T E M P H I G H O I L T E M P An Automatic Reset Safety will shut the entire chiller down on a fault when the safety threshold is exceeded and allows automatic restart after the condition causing the shutdown clears. Restart will occur only after antirecycle timers are satisfied and demand requires. A reset hysteresis is built in to each safety so repetitive faulting and clearing will not occur in a short time period. An example would be if ambient temperature dropped below the cut-out, temperature would have to rise 5 F above the cut-out before the fault lockout would clear and restart can occur. When the chiller is shut down on one of these safeties, a message will appear on the STATUS display informing the operator of the problem. This is accessible by pressing the "STATUS" key. Details concerning each of the three Automatic Reset Safeties follow. Low Water Temperature Safety The Low Water Temperature Safety assures that the evaporator is not damaged from freezing due to improperly set control points. Whenever the chilled liquid temperature drops below the programmable cut-out, the chiller will shut down. The chiller will be re-enabled and the fault will clear when temperature rises 4 F above the cut-out point. YORK INTERNATIONAL 79

80 The Low Water Temperature Safety Cut-out is programmable by the user (Page 61). An example of the Low Water Temperature Fault display message is shown below: C H I L L E R F A U L T : L O W W A T E R T E M P Low Ambient Temperature Safety The Low Ambient Temperature Safety assures that the chiller does not run in low ambients where potential damage could result due to low system pressures. It can also be used to shut down the chiller at a temperature where continued running of the chiller is not economical as compared to the use of free cooling. The Low Ambient Cut-out is programmable by the user (Page 59). If the outdoor ambient temperature drops 1 F below the cut-out, the chiller will shut down. The fault will clear when the temperature rises 1 F above the cut-out. An example of the Low Ambient Temperature Fault display message is shown below: C H I L L E R F A U L T : L O W A M B I E N T T E M P High Ambient Temperature Safety The High Ambient Temperature Safety assures that the chiller does not run in ambients above 130 F where potential malfunction of system mechanical and electrical components may result. The High Ambient Cut-out is programmable (Page 60) and may be adjusted for cut-outs below 130 F. The cut-out may be programmed to cut-out at temperatures from F. Whenever the ambient rises more than one degree F above the cut-out, the chiller will shut down. Restart will occur when temperature drops one degree F below the cut-out. An example of the High Ambient Temperature Fault display message is shown below: C H I L L E R F A U L T : H I G H A M B I E N T T E M P AC Under Voltage Safety The Under Voltage Safety assures that the system is not operated at voltages where malfunction of the microprocessor could result in system damage. Whenever the microprocessor senses an onboard control power supply failure while a compressor is running, the chiller is shut down. The microprocessor circuitry is capable of operating at voltages 10% below the nominal 115VAC supply to the panel. Auto-restart of the chiller will occur when power is reapplied after a 2 minute start-up timer elapses. This timer assures that the motor has a minimum of 2 minutes to cool under any circumstances, allowing much of the internal heating due to starting to be dissipated before another start occurs. An example of the Under Voltage Safety display message is shown below: Flow Switch C H I L L E R F A U L T : V A C U N D E R V O L T A G E The microprocessor monitors the closure of the flow switch to assure that water flow is present in the evaporator which prevents freeze-ups. The flow switch "dry" contacts are connected between terminals 13 & 14 (Fig. xx). If the flow switch opens, the chiller will shut down and the following STATUS message will be displayed: S Y S 1 N O R U N P E R M S Y S 2 N O R U N P E R M Closing of the flow switch, when flow is present, will cause the message to disappear and auto-start to occur. CAUTION: NEVER BYPASS A FLOW SWITCH. THIS WILL CAUSE DAMAGE TO THE CHILLER AND VOID ANY WARRANTIES. Print-out On Fault Shutdown If an optional printer is installed (Page xx), the micro will automatically send the contents of the HISTORY Buffer #1 to the printer anytime a fault shutdown occurs. This will allow record keeping of individual faults, even though they do not cause a lock-out of the system. This information may be useful to identify developing problems and troubleshooting. The NO RUN PERM fault messages will not be stored in the History Buffer and will not cause an auto print-out. NOTE: Due to extreme operating conditions or systems where control deficiencies are present, occasional faults may occur with the associated printout. This may be normal and expected. Do not become alarmed. An example of this print-out is shown in Fig YORK INTERNATIONAL

81 FORM NM2 YORK INTERNATIONAL CORPORATION MILLENNIUM SCREW CHILLER RCC OPTION ENABLED SOFTWARE VERSION W.04F.01 SAFETY SHUTDOWN NUMBER 1 1:32PM 18 JUN 96 SYS 1 HIGH OIL DIFF SHUTDOWN SYS 2 STATUS: NO FAULTS RETURN WATER TEMP 63.2 DEGF LEAVING WATER TEMP 50.1 DEGF LOW WATER CUTOUT 36.0 DEGF COOLING RANGE 42.0 TO 46.0 DEGF TARGET TEMP 44.0 DEGF AMBIENT AIR TEMP 64.9 DEGF LOW AMBIENT CUTOUT 44.0 DEGF LOW PRESSURE CUTOUT 44 PSIG LEAD SYSTEM SYS 1 LOCAL REMOTE SETTING: REMOTE SYSTEM 1 DATA COMPRESSOR STATUS ON RUN TIME D-H-M-S AVERAGE MTR AMPS = %FLA PHASE L1 MTR AMPS = %FLA PHASE L2 MTR AMPS = %FLA PHASE L3 MTR AMPS = %FLA DIFF OIL PRESSURE 92 PSID SUCTION PRESSURE 89 PSID SATURATED SUCTION 52.9 DEGF SUCTION TEMP 66.5 DEGF SUPERHEAT 13.6 DEGF DISCHARGE PRESSURE 279 PSIG SATURATED DISCHARGE DEGF DISCHARGE TEMP DEGF OIL TEMP DEGF LIQUID INJECTION VALVE ON FORWARD FANS 2 REVERSE FANS OFF LIQUID LINE SOLENOID ON RUN PERMISSIVE ON SYSTEM 2 DATA COMPRESSOR STATUS ON RUN TIME D-H-M-S AVERAGE MTR AMPS = %FLA PHASE L1 MTR AMPS = %FLA PHASE L2 MTR AMPS = %FLA PHASE L3 MTR AMPS = %FLA DIFF OIL PRESSURE 0 PSID SUCTION PRESSURE 82 PSIG SATURATED SUCTION 49.0 DEGF SUCTION TEMP 68.3 DEGF SUPERHEAT 19.3 DEGF DISCHARGE PRESSURE 238 PSIG SATURATED DISCHARGE DEGF DISCHARGE TEMP DEGF OIL TEMP DEGF LIQUID INJECTION VALVE OFF FORWARD FANS OFF REVERSE FANS ON LIQUID LINE SOLENOID ON RUN PERMISSIVE ON S M T W T F S *=HOLIDAY SUN MON TUE WED THU FRI SAT HOL START=00:00AM STOP=00:00AM START=06:00AM STOP=08:00PM START=06:00AM STOP=08:00PM START=06:00AM STOP=08:00PM START=06:00AM STOP=08:00PM START=06:00AM STOP=08:00PM START=00:00AM STOP=00:00AM START=00:00AM STOP=00:00AM FIG AUTOMATIC FAULT PRINT-OUT ANTICIPATION SAFETY CONTROLS Anticipation controls are built into the software to prevent safety shutdowns by automatically overriding temperature controls, if system conditions approach safety thresholds. This allows the chiller capacity to avoid total loss of cooling resulting from a lockout on a safety. Anticipation safeties monitor suction and discharge pressure and unload the compressor s as needed. The micro will display a message on the STATUS DISPLAY whenever these controls are in operation. Discharge Pressure Unloading The purpose of this safety is to reduce the chance of faulting on the internal or external high discharge pressure cut-out which will cause total cooling loss in the system. The micro will unload the system in an effort to keep the discharge pressure below the cut-out. For the first 60 seconds of operation, the unloading safety is ignored. After 60 seconds, if discharge pressure exceeds the Discharge Pressure Unload setpoint programmed by the user (Page 60), the micro will unload the affected compressor by sending a one second unload pulse to the slide valve. Continued unloading will occur every 5 seconds until the discharge pressure drops below the programmed setpoint. The micro will automatically extinguish the Status display DSCH LIMITING and reload the compressor, if demand requires, when the discharge pressure drops below 90% of the programmed setpoint. The operation of this safety becomes important if condenser coils become dirty, a problem exists with condenser fan operation, or if extreme ambient or load conditions occur. A STATUS message will be displayed whenever discharge pressure unloading is in effect. An example of this message is shown below: S Y S 1 S Y S 2 Motor Current Unloading D S C H L I M I T I N G D S C H L I M I T I N G The purpose of this safety is to reduce the chance of faulting due to high motor current causing total loss of cooling in the system. The micro will unload the system in an effort to keep the motor current from exceeding the high motor Current Cut-out. For the first 60 seconds of operation, the unloading safety is ignored. After 60 seconds of operation, if motor current exceeds the Current Limit Setpoint programmed YORK INTERNATIONAL 81

82 by the user (Page 78), the micro will unload the affected compressor by sending a one second unload pulse to the slide valve. Continued unloading will occur every 5 seconds until the motor current drops below the programmed setpoint. The micro will automatically extinguish the CURR LIM- ITING Status display and reload the compressor if demand requires and the motor current drops below 90% of the programmed cut-out. The operation of this safety also becomes important when demand limiting is critical due to power requirements or limitations in the building. In some cases current limiting may come into play if abnormally high outdoor temperatures are encountered and high discharge pressures cause motor currents to rise near the safety cut-out point. An example of the Current Limiting display message is shown below: S Y S 1 S Y S 2 Suction Temp Limiting C U R R L I M I T I N G C U R R L I M I T I N G SUCTION LIMITING is only operable when optional electronic expansion valves are added to the chiller. If suction pressure exceeds the programmed pressure, the micro will allow superheat to rise above the setpoint in an attempt to reduce suction pressures. This is done to assure that adequate motor cooling is provided. Normally, the default value is sufficient and programming is not necessary. Details on programming this feature are outlined on page XX. An example of the SUCT LIMITING display message is shown below: S Y S 1 S U C T L I M I T I N G S Y S 2 S U C T L I M I T I N G INTERNAL TIMERS AND PUMPDOWN CONTROLS ANTI-RECYCLE TIMER Anytime a compressor shuts down for any reason, restart cannot occur until the programmable Anti-recycle Timer (Page 61) has timed out (timer starts with the compressor start). Even though the Anti-recycle timer has timed out, a minimum of 2 minutes (2 - minute start-up timer) must always elapse after a compressor shuts down, before it may again restart. If a power failure occurs, the anti-recycle timers will reset to 2 minutes after power is re-applied. If the anti-recycle timer is preventing a start, the timer position in seconds may be viewed by pressing the "STATUS" key. A sample display follows: S Y S 1 S Y S 2 ANTI-COINCIDENCE TIMER A R T M R S A R T M R S The Anti-Coincidence Timer assures that 2 compressors can never start simultaneously which limits excessive current demand. A one minute time delay will always separate compressor starts. The Anti-Coincidence Timer can be viewed, when it is active, by pressing the "STATUS" key. A sample display is shown below: S Y S 1 S Y S 2 PUMPDOWN CONTROLS C O M P R U N N I N G A C T M R 5 6 S Each compressor has a pumpdown on start-up and a pumpdown on shutdown feature. Pumpdown is incorporated into the control scheme to assure that liquid does not enter the compressor on start-up, which could cause damage to the compressor. The pumpdown on start-up control eliminates the need for recycling pumpdown. Eliminating recycling pumpdown saves energy, reduces the number of starts, and saves wear on the compressor/motor. On start-up, the Compressor Slide Valve Unload Solenoid will be energized to unload the compressor and the system will be pumped down to the programmed cut-out or will pump down for 30 seconds, whichever comes first, before the Liquid Line Solenoid (or optional Electronic Expansion Valve) and Economizer Liquid Supply Solenoid is energized. Pumpdown on normal shutdown is incorporated to further assure that liquid does not accumulate in the evaporator. On shutdown, the Compressor Slide Valve Unload Solenoid will be energized to unload the compressor and the Liquid Line Solenoid (or optional Electronic Expansion Valve) and Economizer Liquid Supply solenoid will de-energize. The compressor will continue to operate until the suction pressure reaches the suction pressure cut-out or a period of 30 seconds elapses. Pumpdown on shutdown will occur on "normal" shutdowns. Normal shutdowns include non-safety shut- 82 YORK INTERNATIONAL

83 FORM NM2 downs where cooling demand has been satisfied or when a system switch on the Microprocessor Board is turned off (does not apply to the UNIT Switch). Pumpdown on shutdown will also occur when a flow switch opens or run permissive is lost and when a Daily Schedule or a Remote Shutdown is called for. The following message will be displayed on the STATUS display when a non safety shutdown due to cooling demand, micro board system switch shutdown, or a run permissive/flow switch shutdown occurs. After pumpdown is complete, the respective shutdown message will be displayed for the system. No display indicating a pumpdown will be viewed when a Daily Schedule or a Remote Shutdown occurs. Shutdown messages for Remote and Daily Schedule shutdown will be displayed during pumpdown and after shutdown for these two messages. Manual pumpdown from the control panel is not possible. S Y S 1 P U M P I N G D O W N S Y S 2 P U M P I N G D O W N YORK INTERNATIONAL 83

84 "PRINT" KEYS PRINT KEYS #28164 FIG "PRINT" KEYS GENERAL The "PRINT" keys allow the operator to obtain two different remote hard copy print-outs. A print-out of real-time system operating data and a print-out of system history data at the "instant of the fault" on each of the last three faults which occurred on the chiller is available. These printouts are available by pressing the "OPER DATA" and "HISTORY" keys. If a remote printer is not being used, and the desire is to obtain data locally at the panel, the same keys allow access to identical real-time operating data as well as fault information. This information is available by using a combination of the "OPER DATA" and "HISTORY" keys in conjunction with the "ENTER" key on the keypad. An explanation of the use of the keys for remote printer or local data retrieval will follow. An optional printer (Page xx) will be required for remote printout. REMOTE PRINTOUT Oper Data OPER DATA The "OPER DATA" key allows the operator to remotely obtain a printout of current system operating parameters at the instant that the key is pressed. When the key is pressed, a snapshot will be taken of system operating conditions as well as all of the user programming selections. This data will be temporarily stored in memory, after which, transmission of this data will begin to the remote printer. As the data is transmitted from the microprocessor to the printer, it will be erased from the memory locations where it is temporarily stored in the microprocessor. A sample printout is shown in Fig. 27. History HISTORY The "HISTORY" key allows the operator to remotely obtain a printout of information relating to the last 3 Safety Shutdowns which occurred. The information is stored at the instant of the fault, regardless of whether the fault caused a lockout to occur. The information is also not affected by power failures (long term internal memory battery back-up is built into the circuit board) or manual resetting of a fault lock-out. When the "HISTORY" key is pressed, a Printout is transmitted of all system operating conditions which were stored at the "instant the fault occurred" for each of the last 3 safety shutdowns. The printout will begin with the most recent fault which occurred. 84 YORK INTERNATIONAL

85 FORM NM2 YORK INTERNATIONAL CORPORATION MILLENNIUM SCREW CHILLER RCC OPTION ENABLED SOFTWARE VERSION SYSTEM STATUS 1:29PM 18 JUN 96 SYS 1 COMPRESSOR RUNNING SYS 2 COMPRESSOR RUNNING W.04F.01 RETURN WATER TEMP 63.2 DEGF LEAVING WATER TEMP 50.1 DEGF LOW WATER CUTOUT 36.0 DEGF COOLING RANGE 42.0 TO 46.0 DEGF TARGET TEMP 44.0 DEGF AMBIENT AIR TEMP 64.9 DEGF LOW AMBIENT CUTOUT 44.0 DEGF LOW PRESSURE CUTOUT 44 PSIG LEAD SYSTEM SYS 1 LOCAL REMOTE SETTING: REMOTE SYSTEM 1 DATA COMPRESSOR STATUS ON RUN TIME D-H-M-S AVERAGE MTR AMPS = %FLA PHASE L1 MTR AMPS = %FLA PHASE L2 MTR AMPS = %FLA PHASE L3 MTR AMPS = %FLA DIFF OIL PRESSURE 0 PSID SUCTION PRESSURE 89 PSIG SATURATED SUCTION 52.9 DEGF SUCTION TEMP 66.5 DEGF SUPERHEAT 13.6 DEGF DISCHARGE PRESSURE 279 PSIG SATURATED DISCHARGE DEGF DISCHARGE TEMP DEGF OIL TEMP DEGF LIQUID INJECTION VALVE ON FORWARD FANS 2 REVERSE FANS OFF LIQUID LINE SOLENOID ON RUN PERMISSIVE ON SYSTEM 2 DATA COMPRESSOR STATUS ON RUN TIME D-H-M-S AVERAGE MTR AMPS = %FLA PHASE L1 MTR AMPS = %FLA PHASE L2 MTR AMPS = %FLA PHASE L3 MTR AMPS = %FLA DIFF OIL PRESSURE 0 PSID SUCTION PRESSURE 82 PSIG SATURATED SUCTION 49.0 DEGF SUCTION TEMP 68.3 DEGF SUPERHEAT 19.3 DEGF DISCHARGE PRESSURE 238 PSIG SATURATED DISCHARGE DEGF DISCHARGE TEMP DEGF OIL TEMP DEGF LIQUID INJECTION VALVE OFF FORWARD FANS OFF REVERSE FANS ON LIQUID LINE SOLENOID ON RUN PERMISSIVE ON S M T W T F S *=HOLIDAY SUN MON TUE WED THU FRI SAT HOL START=00:00AM STOP=00:00AM START=06:00AM STOP=08:00PM START=06:00AM STOP=08:00PM START=06:00AM STOP=08:00PM START=06:00AM STOP=08:00PM START=06:00AM STOP=08:00PM START=00:00AM STOP=00:00AM START=00:00AM STOP=00:00AM FIG OPER DATA PRINT-OUT The most recent fault will always be stored as SAFETY SHUTDOWN NO. 1 (See printout Fig. 28). Identically formatted fault information will then be printed for SAFETY SHUTDOWN NO. 2 and SAFETY SHUT- DOWN NO. 3. Information contained in the SAFETY SHUTDOWN Buffers is very important when attempting to troubleshoot a system problem. This data reflects the system conditions at the instant the fault occurred and often reveals other system conditions which actually caused the safety threshold to be exceeded. See Fig. 28 for a sample of the History Buffer Printout. LOCAL DISPLAY READOUT Oper Data OPER DATA The "OPER DATA" key also allows the user to scroll through additional real time display information about the chiller system which is not available from the "DIS- PLAY" keys. This information covers a wide range of data which includes fan status, loading status, liquid line solenoid status, run time, etc. A total of 15 different displays are offered. When the "OPER DATA" key is pressed, the following message will appear: P R E S S E N T E R T O D I S P L A Y D A T A Repetitively pressing the "ENTER" key allows the operator to scroll through the 15 available displays. In the information that follows, a sample message along with an explanation of its meaning is provided for all 15 messages. L O A D T I M E R U N L O A D T I M E R 7 0 S E C 6 0 S E C The top message provides a real time display of the time left on the Load Timer. The Load Timer is a constantly recycling timer that the micro utilizes in conjunction with "rate control" and "temperature deviation from setpoint" to determine when loading should occur. NOTE: This counter may appear to not count according to actual time. This is a result of the micro s algorithm compensating for changing loading requirements. The bottom message provides a real time display of the time left on the Unload Timer. The Unload Timer is a constantly recycling timer that the micro utilizes in conjunction with "rate control" and "temperature deviation from setpoint" to determine when unloading should occur. NOTE: This timer may appear to not count according to actual time. This is a result of the micro s algorithm compensating for changing unloading requirements. YORK INTERNATIONAL 85

86 YORK INTERNATIONAL CORPORATION MILLENNIUM SCREW CHILLER ISN OPTION ENABLED SOFTWARE VERSION W.04F.01 SAFETY SHUTDOWN NUMBER 1 5:30PM 18 JUN 96 CHILLER FAULT: LOW AMBIENT TEMPERATURE SHUTDOWN RETURN WATER TEMP 63.2 DEGF LEAVING WATER TEMP 50.1 DEGF LOW WATER CUTOUT 36.0 DEGF COOLING RANGE 42.0 TO 46.0 DEGF TARGET TEMP 44.0 DEGF AMBIENT AIR TEMP 42.0 DEGF LOW AMBIENT CUTOUT 44.0 DEGF LOW PRESSURE CUTOUT 44 PSIG LEAD SYSTEM SYS 1 LOCAL REMOTE SETTING: REMOTE SYSTEM 1 DATA COMPRESSOR STATUS ON RUN TIME D-H-M-S AVERAGE MTR AMPS = %FLA PHASE L1 MTR AMPS = %FLA PHASE L2 MTR AMPS = %FLA PHASE L3 MTR AMPS = %FLA DIFF OIL PRESSURE 0 PSID SUCTION PRESSURE 89 PSIG SATURATED SUCTION 52.9 DEGF SUCTION TEMP 66.5 DEGF SUPERHEAT 13.6 DEGF DISCHARGE PRESSURE 279 PSIG SATURATED DISCHARGE DEGF DISCHARGE TEMP DEGF OIL TEMP DEGF LIQUID INJECTION VALVE ON FORWARD FANS 2 REVERSE FANS OFF LIQUID LINE SOLENOID ON RUN PERMISSIVE ON SYSTEM 2 DATA COMPRESSOR STATUS OFF RUN TIME D-H-M-S AVERAGE MTR AMPS = %FLA PHASE L1 MTR AMPS = %FLA PHASE L2 MTR AMPS = %FLA PHASE L3 MTR AMPS = %FLA DIFF OIL PRESSURE 0 PSID SUCTION PRESSURE 82 PSIG SATURATED SUCTION 49.0 DEGF SUCTION TEMP 68.3 DEGF SUPERHEAT 19.3 DEGF DISCHARGE PRESSURE 238 PSIG SATURATED DISCHARGE DEGF DISCHARGE TEMP DEGF OIL TEMP DEGF LIQUID INJECTION VALVE OFF FORWARD FANS OFF REVERSE FANS OFF LIQUID LINE SOLENOID OFF RUN PERMISSIVE ON YORK INTERNATIONAL CORPORATION MILLENNIUM SCREW CHILLER ISN OPTION ENABLED SOFTWARE VERSION W.04F.01 SAFETY SHUTDOWN NUMBER 2 3:12PM 18 JUN 96 SYS 1 STATUS: NO FAULTS SYS 2 HIGH OIL TEMP SHUTDOWN RETURN WATER TEMP 63.2 DEGF LEAVING WATER TEMP 50.1 DEGF LOW WATER CUTOUT 36.0 DEGF COOLING RANGE 42.0 TO 46.0 DEGF TARGET TEMP 44.0 DEGF AMBIENT AIR TEMP 64.9 DEGF LOW AMBIENT CUTOUT 44.0 DEGF LOW PRESSURE CUTOUT 44 PSIG LEAD SYSTEM SYS 2 LOCAL REMOTE SETTING: REMOTE SYSTEM 1 DATA COMPRESSOR STATUS ON RUN TIME D-H-M-S AVERAGE MTR AMPS = %FLA PHASE L1 MTR AMPS = %FLA PHASE L2 MTR AMPS = %FLA PHASE L3 MTR AMPS = %FLA DIFF OIL PRESSURE 0 PSID SUCTION PRESSURE 89 PSIG SATURATED SUCTION 52.9 DEGF SUCTION TEMP 66.5 DEGF SUPERHEAT 13.6 DEGF DISCHARGE PRESSURE 279 PSIG SATURATED DISCHARGE DEGF DISCHARGE TEMP DEGF OIL TEMP DEGF LIQUID INJECTION VALVE ON FORWARD FANS 2 REVERSE FANS OFF LIQUID LINE SOLENOID ON RUN PERMISSIVE ON SYSTEM 2 DATA COMPRESSOR STATUS ON RUN TIME D-H-M-S AVERAGE MTR AMPS = %FLA PHASE L1 MTR AMPS = %FLA PHASE L2 MTR AMPS = %FLA PHASE L3 MTR AMPS = %FLA DIFF OIL PRESSURE 0 PSID SUCTION PRESSURE 82 PSIG SATURATED SUCTION 49.0 DEGF SUCTION TEMP 68.3 DEGF SUPERHEAT 19.3 DEGF DISCHARGE PRESSURE 238 PSIG SATURATED DISCHARGE DEGF DISCHARGE TEMP DEGF OIL TEMP DEGF LIQUID INJECTION VALVE OFF FORWARD FANS OFF REVERSE FANS ON LIQUID LINE SOLENOID ON RUN PERMISSIVE ON YORK INTERNATIONAL CORPORATION MILLENNIUM SCREW CHILLER ISN OPTION ENABLED SOFTWARE VERSION W.04F.01 SAFETY SHUTDOWN NUMBER 3 1:32PM 18 JUN 96 SYS 1 HIGH OIL DIFF SHUTDOWN SYS 2 STATUS: NO FAULTS RETURN WATER TEMP 63.2 DEGF LEAVING WATER TEMP 50.1 DEGF LOW WATER CUTOUT 36.0 DEGF COOLING RANGE 42.0 TO 46.0 DEGF TARGET TEMP 44.0 DEGF AMBIENT AIR TEMP 64.9 DEGF LOW AMBIENT CUTOUT 44.0 DEGF LOW PRESSURE CUTOUT 44 PSIG LEAD SYSTEM SYS 1 LOCAL REMOTE SETTING: REMOTE SYSTEM 1 DATA COMPRESSOR STATUS ON RUN TIME D-H-M-S AVERAGE MTR AMPS = %FLA PHASE L1 MTR AMPS = %FLA PHASE L2 MTR AMPS = %FLA PHASE L3 MTR AMPS = %FLA DIFF OIL PRESSURE 92 PSID SUCTION PRESSURE 89 PSIG SATURATED SUCTION 52.9 DEGF SUCTION TEMP 66.5 DEGF SUPERHEAT 13.6 DEGF DISCHARGE PRESSURE 279 PSIG SATURATED DISCHARGE DEGF DISCHARGE TEMP DEGF OIL TEMP DEGF LIQUID INJECTION VALVE ON FORWARD FANS 2 REVERSE FANS OFF LIQUID LINE SOLENOID ON RUN PERMISSIVE ON SYSTEM 2 DATA COMPRESSOR STATUS ON RUN TIME D-H-M-S AVERAGE MTR AMPS = %FLA PHASE L1 MTR AMPS = %FLA PHASE L2 MTR AMPS = %FLA PHASE L3 MTR AMPS = %FLA DIFF OIL PRESSURE 0 PSID SUCTION PRESSURE 82 PSIG SATURATED SUCTION 49.0 DEGF SUCTION TEMP 68.3 DEGF SUPERHEAT 19.3 DEGF DISCHARGE PRESSURE 238 PSIG SATURATED DISCHARGE DEGF DISCHARGE TEMP DEGF OIL TEMP DEGF LIQUID INJECTION VALVE OFF FORWARD FANS OFF REVERSE FANS ON LIQUID LINE SOLENOID ON RUN PERMISSIVE ON FIG HISTORY PRINT-OUT T E M P E R R O R F T E M P R A T E F / M The top message indicates the difference (error) between leaving chilled liquid temperature and the TAR- GET temperature (Desired leaving chilled liquid temperature). The bottom message indicates the rate of change of the leaving chilled liquid temperature in F/minute. The (-) indicates a fall in temperature. No sign indicates a rise in temperature. L E A D S Y S T E M I S S Y S T E M N U M B E R 1 This message informs the operator which system is selected as the lead. E V A P O R A T O R W A T E R P U M P S T A T U S O N This message informs the operator that the micro has commanded the auxiliary contacts (optional) for the evaporator water pump to close. 86 YORK INTERNATIONAL

87 FORM NM2 E V A P O R A T O R H E A T E R S T A T U S O F F S Y S 2 L I Q U I D L I N E S O L E N O I D S T A T U S O N This message informs the operator that the micro senses the outdoor ambient temperature is below 40 F and is commanding the Evaporator Heater to turn on. Once turned on, the heater will turn off at 45 F. S Y S 1 R U N T I M E D - H - M - S This message displays the accumulated Run Time on SYS 1 since the last start. This time is recorded in Days (D), Hours (H), Minutes (M), and Seconds (S). This message informs the operator that the SYS 2 Liquid Line Solenoid is "OFF" (De-energized/Closed) or "ON" (Energized/Open). S Y S 2 L I Q U I D I N J E C T I O N V A L V E O F F This message informs the operator that the micro is or is not activating the liquid injection valve for SYS 2 for oil cooling. S Y S 2 F O R W A R D F A N S S T A T U S O F F S Y S 1 L I Q U I D L I N E S O L E N O I D S T A T U S O N This message informs the operator of the number of forward running pairs of condenser fans on SYS 2. This message informs the operator that the SYS 1 Liquid Line Solenoid is "OFF" (De-energized/Closed) or "ON" (Energized/Open). S Y S 2 R E V E R S E F A N S T A T U S O F F S Y S 1 L I Q U I D I N J E C T I O N V A L V E O N This message informs the operator whether the pair of reversing fans are running on SYS 2. This message informs the operator that the micro is or is not activating the liquid injection valve for SYS 1 for oil cooling. S Y S 1 F O R W A R D F A N S S T A T U S 2 This message informs the operator of the number of forward running pairs of condenser fans on SYS 1. S Y S 1 R E V E R S E F A N S T A T U S O F F This message informs the operator whether the pair of reversing condenser fans are running on SYS 1. S Y S 2 R U N T I M E D - H - M - S This message displays the accumulated Run Time on SYS 2 since the last start. This time is recorded in Days (D), Hours (H), Minutes (M), and Seconds (S). History HISTORY The "HISTORY" key also allows the user to scroll through the SAFETY SHUTDOWN display information relating to the last 3 Safety Shutdowns which occurred. Information contained in the micro s SAFETY SHUT- DOWN buffers is very important when attempting to troubleshoot a system problem. This data reflects system conditions at the instant the fault occurred. Information is stored in the SAFETY SHUTDOWN buffers on every fault regardless of whether the fault caused a Lockout to occur. The stored information is also not affected by power failures (long term internal battery back-up is built into the printed circuit board) or manual resetting of a fault lock-out. When the "HISTORY" key is pressed, the following message will appear: D I S P L A Y S A F E T Y S H U T - D O W N N O. 1 ( 1 T O 3 ) The operator must select which of the last three SAFETY SHUTDOWN s is desired. When deciding this, YORK INTERNATIONAL 87

88 keep in mind that SAFETY SHUTDOWN No. 1 is always the most recent fault. As new fault information is stored, it is assigned as No. 1, No. 1 is assigned to No. 2, No 2 is assigned to No. 3, and information stored previously as No. 3 is discarded. To select a SAFETY SHUTDOWN, simply press a "1", "2", or "3" key and press "ENTER". Repetitively pressing the "ENTER" key will allow the operator to scroll through the information available in the SAFETY SHUTDOWN buffer. In the information that follows, a sample message along with an explanation is provided for all available messages: S H U T D O W N O C C U R R E D 5 : 5 9 A M 2 9 N O V 9 5 This message informs the operator of the time and date of the fault. S Y S 1 H I G H O I L D I F F S Y S 2 N O F A U L T S This message informs the operator of the nature of the fault which occurred. R E T U R N W A T E R T E M P F This message indicates the Return Water Temperature at the time of the fault. L E A V I N G W A T E R T E M P F This message indicates the Leaving Water Temperature at the time of fault. L O W W A T E R C U T O U T F This display shows the Low Water Cut-out (Leaving) which was programmed at the time of the fault. C O O L I N G R A N G E T O F This message shows the Cooling Range (CONTROL RANGE, CR) which was programmed at the time of the fault. T A R G E T T E M P F This display shows the TARGET Temperature which was programmed at the time of the fault. A M B I E N T A I R T E M P F This message indicates the Outdoor Ambient Air Temperature at the time of the fault. L O W A M B I E N T C U T O U T 0. 0 F This display shows the Low Ambient Cut-out programmed at the time of the fault. L O W P R E S S U R E C U T O U T 4 4 P S I G This display shows the Low Suction Pressure Cut-out programmed at the time of the fault. L E A D S Y S T E M S Y S 1 This message indicates which system was in the lead at the time of the fault. L O C A L R E M O T E S E T T I N G R E M O T E This message shows whether remote or local communications has been selected. "LOCAL" mode will allow an ISN or an RCC option panel to receive chiller data from the chiller through the RS-485 port, but not change programmed values remotely. "REMOTE" mode will allow an ISN or an RCC option panel to receive chiller data and change programmable values remotely. S Y S 1 C O M P R E S S O R O N This message indicates whether Compressor 1 was ON or OFF at the time of the fault. S Y S 1 R U N T I M E D - H - M - S This message shows the Run Time logged on SYS 1, since the last start, in Days (D), Hours (H), Minutes (M), and Seconds (S). 88 YORK INTERNATIONAL

89 FORM NM2 S Y S 1 A V G M O T O R A M P S % F L A 9 0 A M P S This message indicates SYS 1 % FLA and Average Motor Current at the time of the fault. S Y S 1 D S C H P R E S S P S I G This message indicates SYS 1 Discharge Pressure at the time of the fault. S Y S 1 P H A S E L % F L A 8 9 A M P S This message shows SYS 1 % FLA Motor Current in Phase L1 at the time of the fault. S Y S 1 P H A S E L % F L A 8 9 A M P S This message shows SYS 1 % FLA Motor Current in Phase L2 at the time of the fault. S Y S 1 P H A S E L % F L A 8 9 A M P S This message shows SYS 1 % FLA Motor Current in Phase L3 at the time of the fault. S Y S 1 O I L P R E S S U R E 1 2 P S I D This display shows the Oil Pressure of SYS 1 at the time of the fault. S Y S 1 S U C T I O N P R E S S 5 9 P S I G This display shows the Suction Pressure of SYS 1 at the time of the fault. S Y S 1 S A T S U C T T E M P F This message indicates the Saturated Suction Temperature of SYS 1 at the time of the fault. S Y S 1 S U C T I O N T E M P F This message indicates SYS 1 Suction Line Temperature at the time of the fault. S Y S 1 S A T D S C H T E M P F This message indicates SYS 1 Saturated Discharge Temperature at the time of the fault. S Y S 1 D I S C H A R G E T E M P F This message indicates SYS 1 Discharge Gas Temperature in the oil separator at the time of the fault. S Y S 1 O I L T E M P F This display shows the Oil Temperature of SYS 1 at the time of the fault. S Y S 1 L I Q U I D I N J E C T I O N V A L V E O F F This message indicates that the Liquid Injection Solenoid Valve of SYS 1 was either energized (ON) or de-energized (OFF) at the time of the fault. S Y S 1 F O R W A R D F A N S 2 This display indicates the number of pairs of fans SYS 1 which were running in the forward direction at the time of the fault. S Y S 1 R E V E R S E F A N S O F F This message indicates whether a pair of fans on SYS 1 were running in the reverse direction at the time of the fault. S Y S 1 S U P E R H E A T F This message indicates SYS 1 superheat at the time of the fault. S Y S 1 L I Q L I N E O N This display informs the operator whether SYS 1 liquid line solenoid valve was energized (ON) or de-energized (OFF) at the time of the fault. YORK INTERNATIONAL 89

90 S Y S 1 R U N P E R M I S S I V E O N This message informs the operator if SYS 1 Run Permissive (flow switch, remote START/STOP) was in the "RUN" mode (ON/closed) or "STOP" mode (OFF/open). S Y S 2 C O M P R E S S O R O N This message indicates whether Compressor 2 was ON or OFF at the time of the fault. S Y S 2 R U N T I M E D - H - M - S This message shows the Run Time logged on SYS 2, since the last start, in Days (D), Hours (H), Minutes (M), and Seconds (S). S Y S 2 A V G M O T O R A M P S % F L A 9 0 A M P S This message indicates SYS 2 % FLA and Average Motor Current at the time of the fault. S Y S 2 P H A S E L % F L A 8 9 A M P S This message shows SYS 2 % FLA Motor Current in Phase L1 at the time of the fault. S Y S 2 P H A S E L % F L A 8 9 A M P S This message shows SYS 2 % FLA Motor Current in Phase L2 at the time of the fault. S Y S 2 P H A S E L % F L A 8 9 A M P S This message shows SYS 2 % FLA Motor Current in Phase L3 at the time of the fault. S Y S 2 O I L P R E S S U R E 1 0 P S I D This display shows the Oil Pressure of SYS 2 at the time of the fault. S Y S 2 S U C T I O N P R E S S 5 9 P S I G This display shows the Suction Pressure of SYS 2 at the time of the fault. S Y S 2 S A T S U C T T E M P F This message indicates the Saturated Suction Temperature of SYS 2 at the time of the fault. S Y S 2 S U C T I O N T E M P F This message indicates SYS 2 Suction Line Temperature at the time of the fault. S Y S 2 S U P E R H E A T F This message indicates SYS 2 superheat at the time of the fault. S Y S 2 D S C H P R E S S P S I G This message indicates SYS 2 Discharge Pressure at the time of the fault. S Y S 2 S A T D S C H T E M P F This message indicates SYS 2 Saturated Discharge Temperature at the time of the fault. S Y S 2 D I S C H A R G E T E M P F This message indicates SYS 2 Discharge Gas Temperature in the oil separator at the time of the fault. S Y S 2 O I L T E M P F This display shows the Oil Temperature of SYS 2 at time of the fault. 90 YORK INTERNATIONAL

91 FORM NM2 S Y S 2 L I Q U I D I N J E C T I O N V A L V E O F F S Y S 2 L I Q L I N E O N This message indicates that the Liquid Injection Solenoid Valve of SYS 2 was either energized (ON) or de-energized (OFF) at the time of the fault. This display informs the operator whether SYS 2 liquid line solenoid valve was energized (ON) or de-energized (OFF) at the time of the fault. S Y S 2 F O R W A R D F A N S O N This display indicates the number of pairs of fans on SYS 2 which were running in the forward direction at the time of the fault. S Y S 2 R U N P E R M I S S I V E O N This message informs the operator if SYS 1 Run Permissive (flow switch, remote START/STOP) was in the "RUN" mode (ON/closed) or "STOP" mode (OFF/open). S Y S 2 R E V E R S E F A N S O F F This message indicates whether a pair of fans on SYS 2 were running in the reverse direction at the time of the fault. YORK INTERNATIONAL 91

92 "CLOCK" KEYS CLOCK KEYS #28164 FIG "CLOCK" KEYS GENERAL The "CLOCK" is an internal system feature that allows the microprocessor to continuously monitor the time of the day. The micro will display the actual time as well as the day of the week and the date on the control panel display, if programmed. The internal clock allows the microprocessor to provide an internal automatic time clock feature for starting and stopping the chiller for each individual day of the week. Also provided is a "HOLI- DAY" feature which allows special start / stop programming for designated holidays. The internal clock and schedule programming eliminates the need for an external time clock. Automatic chiller start and stop will occur according to the programmed schedule. If the user decides not to utilize the schedule feature, the SET SCHEDULE / HOLIDAY can be programmed to run the chiller on demand as long as the "UNIT" and "SYS" switches are ON. Typical display messages will be shown which apply to each key. PROGRAMMING THE DAY, SET TIME & THE DATE Set Time SET TIME A message showing the day, time and date will be displayed when the "SET TIME" key is pressed. T O D A Y I S M O N 1 1 : 1 2 A M 1 9 F E B 9 5 When the display appears, the cursor will be below the first digit of the time. Press the "ADVANCE DAY" key until the proper day appears. Key in the time (hour and minute). Be sure to key in a "0" before the other digits for times before 10 o clock. i.e. 08:31. After the time is keyed in, the cursor will advance to the AM/PM designation. To reprogram, press the "AM/PM" key. When the key is pressed, the display will change to the opposite time period. NOTE: The "AM/PM" key can be pressed once. If an error is made, press the "CANCEL" key and begin again. 92 YORK INTERNATIONAL

93 FORM NM2 After programming AM/PM or if no change is required, begin keying in the required date (the cursor will automatically skip to the first digit of the date (day) when a "number key" is pressed and the number will be placed in the first digit of the day. The sequence of the display is day, month, and year. Two digits must always be entered for both the day and the year. Be sure to key in a "0" for days 1-9 ie: 02 FEB 95 Finish keying in the day. The cursor will automatically skip to the first digit of the year. Key in the year as required. Finally, change the month as needed by repetitively pressing the "+/-" key until the proper month appears. Once the desired information is keyed in, it may be stored into memory by pressing the "ENTER" key. The micro will accept any valid time or date. If an out of range value is entered, the micro will display the following message for 3 seconds before it reverts back to the SET TIME display message to let the user know that another try at reprogramming is necessary. O U T O F R A N G E T R Y A G A I N! NOTE: The displayed time will not update when the SET TIME display is first pressed. The reason is that the micro is waiting for the time to be programmed. To see the time update, press the "SET TIME" key a second time. The cursor will disappear and the "live" clock will be displayed. PROGRAMMING THE DAILY START / STOP AND HOLIDAY SCHEDULE Set Schedule / Holiday SET SCHEDULE /HOLIDAY Messages showing the start / stop schedule of each day of the week as well as the holiday start / stop schedule can be displayed after the "SET SCHEDULE / HOLI- DAY" key is pressed. The display can be scrolled through day-by-day simply by repetitively pressing the "ENTER" or "ADVANCE DAY" key. A typical daily schedule display is shown below: M O N S T A R T = 0 6 : 0 0 A M S T O P = 0 5 : 3 0 P M To reprogram any of the daily schedules, key in the new START time. To change the AM/PM associated with the START time, press the "AM/PM" key. This will change the AM/PM message to the opposite time period. The "AM/PM" key can only be pressed once. If an error is made, press CANCEL and begin reprogramming again. After a change is made to the AM/PM, the cursor will automatically move to the STOP time. If no change is made to the AM/PM, begin keying in the first digit of the desired stop time. The cursor will automatically move to the STOP time, putting in the number which was pressed as the first digit. Key in the STOP TIME with the appropriate AM/PM and press the "ENTER" key. When the "ENTER" key is pressed, the new START / STOP time is entered and the display will scroll to the next day. If an unacceptable time is entered, the following message will be displayed. O U T O F R A N G E T R Y A G A I N! CAUTION: Any Start / Stop times "ENTERED" for Monday will automatically be programmed in for the following days of the week. Be aware of this anytime the SCHEDULE is changed. To scroll through the days to view times programmed, use the "ADVANCE DAY" key, not the "ENTER" key. This will assure that after viewing MONDAY, the "ENTER" key is not pressed which will change times programmed for the remainder of the week. If the chiller is not cycled by the DAILY SCHEDULE, but is required to run whenever the system switches are on, all s should be programmed into the daily schedule. This can be done manually for each day or by pressing "CANCEL" and "ENTER" when the MONDAY START / STOP schedule appears. NOTE: This will have no effect on the holiday schedule. If the chiller is not required to run on a given day, the START time should be programmed for 00:00 AM and the STOP time should be programmed for 12:00 AM. Continue to program each day as needed. After SUN has been entered, the HOLIDAY message will be displayed. H O L S T A R T = 0 8 : 3 0 A M S T O P = 1 2 : 0 0 P M The Holiday (HOL) START / STOP allows the user to designate a specific day(s) for special requirements. This is provided so that a day(s) needing special start / stop requirements can be programmed without disturbing the normal working schedule. The start / stop times for the Holiday schedule are programmed just as any other day. NOTE: Only one start / stop time can be programmed which will apply to each of the days selected as a "HOLIDAY". YORK INTERNATIONAL 93

94 After the "ENTER" key is pressed, a new message will be displayed to designate which days of the week are holidays. S M T * W T F S H O L I D A Y N O T E D B Y * In the above sample display, an * designates Tuesday as a holiday. When the display appears, the cursor will first stop behind Sunday. To designate a day as a holiday, press the "*" key. If a day is not to be a holiday, press the "0" key. Whenever the "*" or the "0" keys are pressed, the cursor will advance to the next day. After all the holiday days are programmed, press "ENTER" to store the new data into memory. The display will then advance to the beginning of the Daily Schedule (MON). The Holiday Schedule is only executed once by the micro before it is erased from memory. This is done because in most cases a special Holiday Schedule is only necessary once in a several month period. It also eliminates the need for operator intervention to erase the schedule after the holiday passes. If an error is made while programming or a change is required, press "CANCEL". This will clear the programmed (*) "Holiday" days. The schedule can then be reprogrammed. The "0" key will not cancel out a "*" and cannot be used for correcting a programming error. Manual Override MANUAL OVERRIDE When the "MANUAL OVERRIDE" key is pressed, the DAILY Schedule programmed into the chiller will be ignored and the chiller will start up when water temperature allows, unit switches permits, remote cycling device permits, and system switches permit. Normally this key is not used unless an emergency forces the chiller to require operation during a period where the programmed Daily Schedule is calling for the chiller to be OFF (Daily Schedule Shutdown). Once activated, MANUAL OVERRIDE is only active for a period of 30 minutes. It is for servicing only and is designated so that if selected and operated unattended, the microprocessor will automatically return to the Daily Schedule. 94 YORK INTERNATIONAL

95 FORM NM2 UNIT ON/OFF SWITCH, SYSTEM SWITCHES AND OTHER CONTROLS UNIT ON/OFF SWITCH #28164 FIG UNIT ON/OFF SWITCH UNIT ON/OFF SWITCH A master UNIT ON/OFF switch is located on the keypad. This rocker switch allows the operator to turn the entire chiller OFF if desired. The switch must be placed in the ON position for the chiller to operate. Whenever the switch is placed in the OFF position, a STATUS display indicating the condition will be displayed. This message is shown below: U N I T S W I T C H I S I N T H E O F F P O S I T I O N SYSTEM SWITCHES SYSTEM SWITCHES 1-4 are located on the Microprocessor Board (See Fig. 31). These allow the operator to selectively turn a given system on or off as desired. On a 2 system chiller, switches 3 & 4 should be OFF. The System Switch for a designated system must be ON (Switch to the right) for the system to operate. Whenever a switch is placed in the OFF position, a STATUS message is displayed indicating that the system does not have a Run Permissive signal. An example of this message is shown below: S Y S 1 S Y S S W I T C H O F F S Y S 2 S Y S S W I T C H O F F NOTE: This message will not appear if the Anti-recycle or Anti-coincident timers are in effect and are being displayed. ALARM CONTACTS (ANNUNCIATION ALARM) "Dry" contacts connected to terminals 23 and 24 of TB1 (Fig. 32) are supplied which will transition to function as a warning whenever a fault lock-out occurs on any system or if power is lost to the control panel. The dry contacts are normally open (N.O.) and will close when control power is applied to the panel, if no fault conditions are present. When a fault occurs or power is lost, the contacts open. A 28VDC or 120VAC external alarm circuit (supplied by others) may be wired into the YORK supplied alarm contacts. Any inductive load devices (relay or contactor) supplied by the user, which are connected to the dry YORK INTERNATIONAL 95

96 MICROPROCESSOR BOARD SYSTEM SWITCHES 1-4 ON MICROPROCESSOR BOARD #27962 #26001 FIG LOCATION OF THE MICROPROCESSOR BOARD AND SYSTEM SWITCHES alarm contacts, MUST be suppressed at the load. (Connect the suppressor across the coil of the relay or contactor.) Use YORK P/N suppressor (Typically, several are supplied loose with the panel). Failure to install suppressors will result in nuisance faults and possible damage to the chiller. MAIN ELECTRICAL CONTROL PANEL CAUTION: If the alarm circuit is applied in an application used for critical duty (such as process duty or cooling other critical equipment) and the alarm circuit should fail to function, YORK will not be liable for damages. LEAD/LAG COMPRESSOR SELECTION The chiller may be set up for AUTO or MANUAL Lead/Lag. This is accomplished by properly configuring the S1 Dip Switches on the Microprocessor Board. Details for configuring the switches are discussed in the DISPLAY KEY Section under "OPTIONS" key. When AUTO Lead/Lag is utilized, the micro attempts to balance run time between the two compressors. A num- TB1 FIG ALARM CONTACT CONNECTION LOCATION OF TB1 96 YORK INTERNATIONAL

97 FORM NM2 ber of conditions can occur which will prevent this from happening. Factors determining lead/lag selection and the resulting lead/lag determination are discussed below: 1. The micro automatically defaults the lead to SYS 1 and the lag to SYS 2 if both compressors are ready to start (Anti-recycle Timers timed out) and compressors have equal run time. 2. If both compressors are ready to start (Anti-recycle Timers timed out), the compressor with the lowest run hours will start first. 3. If both compressors are waiting to start (Anti-recycle Timers are not timed out), the micro will assign the lead to the compressor with the shortest anti-recycle time in an effort to provide cooling quickly. 4. If the lead compressor is locked out, faulted and waiting to restart, SYS switch on the micro board is off, or a run permissive is keeping an individual system from running, the lag compressor is swapped to the lead. This is true regardless of whether the lag compressor is on or off. If MANUAL Lead/Lag is selected, an external "dry" contact (switch) must be wired into the chiller. This contact is field supplied. With the contact open, SYS 1 is placed in the lead. When the contact is closed, SYS 2 will be lead system. Manual Lead/Lag selection will be automatically overridden by the micro to allow the lag compressor to automatically become the lead anytime the selected lead compressor shuts down due to a lock-out, lead system faults and is waiting to restart, lead system switch on the micro board is in the OFF position, or if a run permissive is keeping the lead of the system off. Automatic switchover in the "MANUAL" mode is provided to try to maintain chilled liquid temperature as close to setpoint as possible. The "dry" contact for manual lead/lag selection is wired into terminals 13 and 19 of the TB3 Terminal Block. The location of these contacts is shown in Fig. 33. MEMORY BATTERY BACK-UP The Microprocessor Board contains a Real Time Clock (RTC) I. C. Chip with an internal battery back-up. This battery back-up assures that any programmed values (setpoints, etc.), clock, all fault information, and accumulated information such as starts/run time, etc. stored in the RTC memory is not lost when a power failure occurs, regardless of the length of the power loss. The battery is a 10 year lithium type. The life of the battery will depend upon whether the Real Time Clock s internal clock circuit is energized. With the clock OFF, a TB3 #27962 FIG TB3 LOCATION MANUAL LEAD LAG rated life of approximately 10 years can be expected. With the clock ON, approximately 5 years. The clock is turned ON and OFF by a jumper on the Microprocessor Board. While a chiller is operating, the clock must be ON. Otherwise the internal clock on the microprocessor will not be active and the micro cannot keep track of time, although all other functions will operate normally. Failure to turn the Clock ON could result in the chiller not starting due to the time frozen on the clock falling outside the START/STOP time window that is programmed in the DAILY SCHEDULE. If the chiller is shut down for extended periods of months, it may be desirable to disable the clock to save battery life. The clock can then be reactivated and reprogrammed when the chiller is returned to service. NOTE: ALL PROGRAMMED VALUES AND STORED DATA, OTHER THAN THE INTERNAL CLOCK TIME-KEEPING, WILL BE MAINTAINED IN MEMORY REGARDLESS OF WHETHER THE CLOCK IS ON OR OFF AND REGARDLESS OF THE LENGTH OF THE POWER FAILURE. To disable the clock, place the jumper (Fig. 34) in the OFF position. To activate it, place the jumper in the ON position. YORK INTERNATIONAL 97

98 On power-up the microprocessor will check the Real Time Clock (RTC Chip) battery to assure that the internal battery is still operational. This is accomplished by performing an RTC RAM location check. As long as the battery checks out, the micro will continue on with business without interruption. CLOCK JUMPER If a check is made and the battery has failed, the microprocessor will not allow the chiller to run and the following STATUS message will appear:!! W A R N I N G!!!! L O W B A T T E R Y!! Under low battery conditions, the only way to run the chiller is to press the "MANUAL OVERRIDE" key. The "MANUAL OVERRIDE" key will function differently than it does in service situations where it overrides the daily schedule for only 30 minutes. In a low battery condition, the "MANUAL OVERRIDE" key will zero out the daily schedule to allow unlimited operation regardless of the time on the internal clock. Default values will also be loaded into memory for all setpoints and cut-outs. These may require reprogramming to assure they meet the chiller operating requirements for operation board 30 minutes. In addition, the low battery message which is displayed for this condition will disappear. NOTE: If a power failure should again occur, the above process will again need to be repeated to bring the chiller back on line. In the unlikely event the low battery message should ever appear, it will require the RTC Chip U13 on the Microprocessor Board (Fig. 34) to be replaced. Care should be taken to assure that the chip is properly installed. Pin 1 (dimple in the top of the chip) must be oriented as shown in Fig. 34. The part number of the RTC Chip is COMPRESSOR HEATER The Compressor Heater in each compressor will be ON for the first five minutes after the compressor is shut down. Then the heater is controlled by discharge temperature. If the heater is ON and the discharge temperature rises above 170 F will shut off. If the heater is OFF and the discharge temperature falls below 100 F, it will turn ON. The heater is controlled by the microprocessor. The purpose of the heater is to prevent the migration of refrigerant into the compressor during shutdown, assuring proper lubrication of the compressor on start-up. Anytime power is removed from th chiller for more than an hour, 115 VAC control power should be reapplied to allow the compressor heaters to remain on for 24 hours prior to restart. #26001 FIG CLOCK JUMPER EVAPORATOR HEATER The evaporator heater prevents water standing in the evaporator from, freezing. Whenever the outdoor ambient temperature drops below 40 F, the microprocessor will turn the evaporator heaters ON. If temperature rises above 45 F, the heater will be turned off. METRIC DISPLAY The control panel is capable of providing displays of pressures and temperatures in metric values. Temperatures will be displayed in C and pressures in Bars. A Metric to English temperature conversion table is provided on the rear cover of this manual. Pressure can be converted from PSIG to Bars using the formula 1 Bar = PSIG. To obtain displays in Metric, Switch 5 Dip switch S1 on the Microprocessor Board must be placed in the closed (on) position (Page xx). The positioning of this switch can be verified by pushing the OPTIONS key and verifying that "SI UNITS READOUT" is programmed (Page xx). 98 YORK INTERNATIONAL

99 FORM NM2 EMS/BAS CONTROLS The microprocessor is capable of REMOTE START/STOP, REMOTE SETPOINT RESET, and RE- MOTE CURENT RESET. These functions can be easily utilized by connecting user supplied "dry" contacts to the Microprocessor Board. REMOTE START/STOP BY A CYCLING DEVICE OR TIME CLOCK Remote START/STOP is accomplished by connecting a time clock or other "dry" contact in series with the flow switch on terminals 13 & 14 of TB4. See Fig. 11 for the location of the terminals. The contact must be closed to allow the chiller to run. Any time the contact opens, the chiller will shut down and the following status message will be displayed. S Y S # 1 N O R U N P E R M S Y S # 2 N O R U N P E R M Wiring from these contact should not exceed 25ft. and should be run in grounded conduit that does not carry any wiring other than control wiring. Additionally, if an inductive device (relay, contactor) is supplying these contacts, the coil of the device must be suppressed with a user supplied YORK P/N suppressor. REMOTE SETPOINT RESET (REMOTE RESET TEMP RANGE) Remote Setpoint Reset allows resetting the setpoint upward from the programmed value in memory. This is accomplished by connecting a "dry" contact between terminals 13 & 17of TB4. See Fig. xx for the location of these terminals. Closing the contact for a defined period of time allows reset of the setpoint upward by up to 40 F above the setpoint programmed in memory. The maximum desired reset must be programmed into memory and can be a value of 02 to 40 F. This value will vary according to the user s requirements. To program the reset, press the REMOTE SETPOINT TEMP RANGE key. The following message will appear. R E M S E T P O I N T = R E M R A N G E = 4 0 F The display will indicate the REM SETPOINT which is always equal to the chilled liquid setpoint programmed by the CHILLED LIQUID TEMP/RANGE key plus the offset from the remote reset signal. The dsplay will also show the REM RANGE which is the same as the maximum reset required by the application. Key in the maximum reset required for the application after REM RANGE and press the ENTER Key to store the new value in memory. Once the maximum reset is programmed, it will require a contact closure of 21 seconds to achieve the maximum reset. Closure for less than 21 seconds will provide a smaller reset. For noise immunity, the micro will ignore closures of less than 1 second. To compute the offset for a given contact closure, use the formulas below: 1. Programmed max. reset = Reset per sec. 20 seconds 2. (Time Closed-1) Reset per sec. = Reset Example: Programmed max reset - 30 ; Time Closed = 9 sec sec. = 1.5 per sec. 2. (9sec. -1 sec.) 1.5 per sec. = 12 = Reset To determine the new setpoints, add the reset to the setpoint programmed into memory. In the example above, if the programmed setpoint = 44 F, the new setpoint after the 9 second contact closure would be 44 F + 12 F = 56 F. This new setpoint can be viewed on the display by pressing the REMOTE RESET TEMP/RANGE key. To maintain a given offset, the micro must be refreshed every 30 seconds - 30 minutes with a contact closure of the required time period. It will not accept a refresh sooner than 30 seconds after the end of the last PWM signal, but must be refreshed before a period of 30 minutes expires from the end of the last PWM signal. After 30 minutes, if no refresh is provided, the setpoint will change back to its original value. A refresh is nothing more than a contact closure for the period required for the desired offset. NOTE: After an offset signal, the new REM SETPOINT may be viewed on the REMOTE RESET TEMP RANGE DISPLAY. However, if this display is being viewed when the reset pulse occurs, the setpoint will not change on the display. To view the new offset, first press any other display key on the keypad and then press the REMOTE RESET TEMP RANGE key. The new setpoint will then appear. Wiring from these contacts should not exceed 25 ft. and should be run in grounded conduit that does not carry any wiring other than control wiring. Additionally, if an YORK INTERNATIONAL 99

100 inductive device (relay, contactor is supplying these contacts, the coil of the device must be suppressed with a user supplied YORK P/N suppressor. NOTE: REMOTE SETPOINT RESET will not operate when a Remote Control Center Option Kit is connected to the Micropanel. The Remote Control Center will always determine the setpoint. REMOTE % CURRENT LIMIT SETPOINT RESET Remote Current Reset allows resetting the % Current Limit downward from the programmed value in memory. This can be use for demand limiting, etc. Current Reset accomplished by connecting a "dry" contact between terminals 13 & 16. See Fig. xx for the location of these terminals. Closing the contact for a defined period of time allows reset of the % Current Limit downward. Contact closure of 1-18 sec will allow % Current Limiting to be adjusted downward from 115% by a maximum of 85%. This will allow current limiting to a minimum value of 30% FLA (115%-85% = 30%). The Current Limiting will operate independently of the Programmable Current Limiting (See Page xx). The micro will always look at the two Current Limit Setpoints and choose the lower of the two as the controlling value, whenever Remote Current Limiting is utilized. Contact closures of less than 1 second will be ignored. A closure of 18 seconds is the maximum allowable closure and provides a Current Limit reduction of 85%. The required contact closure can be computed by following the 4 steps beow: 1. Choose the % FLA desired for the Current Limit % FLA, after offset. 2. Subtract the desired Current Limit % FLA from 115% to calculate the required offset %. See the formula below: Offset % = 115% - Desired Current Limit % FLA 3. Convert the offset % to a decimal equivalent by dividing by 100%. This will compute the offset. see the formula below: Offset = Offset % 100% 4. Calculate the Pulse Width (PW) in seconds required by utilizing the following formula: Show below is an example where 75% FLA is Desired Current Limit %: 1. 75% is the chosen Current Limit % FLA after offset. 2. Offset % = 115%-75% = 40% 3. Offset = 40% = % 4. PW = (.40 x 20) + 1 = 9 seconds NOTE: The lowest Current Limit % FLA as dictated by the Remote Current Limit Reset (EMS Current Limiting), or ISN Current Limiting. Whenever current is being limited by a remote reset signal, the following STATUS message will appear: S Y S 1 E M S L I M I T I N G S Y S 2 E M S L I M I T I N G Wiring from remote contacts should not exceed 25 ft. and should be run in grounded conduit that does not carry any wiring other than control wiring. Additionally, if an inductive relay contactor is supplying these contacts, the coil of the device must be suppressed with a user supplied YORK P/N suppressor. NOTE: Remote EMS Reset will not operate when a Remote Control Center Option Kit is connected to the micropanel. The Remote Control Center will always determine the setpoint. To maintain a given offset, the micro must be refreshed every 30 seconds - 30 minutes with a contact closure of the required time period. It will not accept a refresh sooner than 30 seconds after the end of the last PWM signal, but must be refreshed before a period of 30 minutes expires from the end of the last PWM signal. After 30 minutes, if no refresh is provided, the setpoint will change back to its original value. A refresh is nothing more than a contact closure for the period required for the desired offset. NOTE: After an offset signal, the new REM SETPOINT may be viewed on the REMOTE EMS LIMIT- ING DISPLAY. However, if this display is being viewed when the reset pulse occurs, the setpoint will not change on the display. To view the new offset, first press any other display key on the keypad and then press the REMOTE EMS LIMITING RANGE key. The new setpoint will then appear. PW seconds = (Offset x 20) YORK INTERNATIONAL

101 FORM NM2 FAN CONTROL STRATEGY The chiller is equipped with 8 condenser fans; 4 per system. Fan control from discharge pressure is standard. Fan start/stop pressures are programmable in the PROGRAM Mode (page xx) under the FAN CONTROL DISCHARGE PRESSURE SETPOINT and FAN ON/OFF PRESS DIFF displays. Ambient temperature has no effect on fan cycling. When discharge pressure reaches the programmed setpoint, the first pair of fans on a respective system starts. After the first pair of fans are brought on in the reverse direction, discharge pressure must rise an additional 20 PSIG above the setpoint before a second pair of fans will be brought on in the forward direction. When this pair of fans starts, the reversing fans will turn off. If discharge pressures rises 40 PSIG above the setpoint, a second pair of fans will start in the forward direction. This is the same pair of fans that orioginally ran in the reverse direction. The first pair of forward fans will also continue to run. The point at which each pair of fans cycles off is also programmable. This is accomplished in the PROGRAM Mode when the FAN ON/OFF PRESS DIFF display appears. The programmable "differential" establishes the pressure at which each pair of fans turn off. The "differential" is the amount the discharge pressure must drop below the pressure at which the fan turned on. FAN 1 & 3 REV (SYS 1) OR 5 & 7 REV (SYS 2) 2 & 4 FOR (SYS 1) OR 6 & 8 FOR (SYS 2) 1 & 3 FOR (SYS 1) OR 5 & 7 (SYS 2) FAN RELAY 9M & 10M 15M & 16M 6M & 8M 12M & 14M 5M & 7M 11M & 13M ON SETPOINT SETPOINT SETPOINT +20 PSIG SETPOINT + 20 PSIG SETPOINT +40 PSIG SETPOINT + 40 PSIG PRESSURE FIG FAN LOCATION / OPERATION OFF SETPOINT - DIFF. SETPOINT - DIFF. SETPOINT +20 PSIG - DIFF SETPOINT +20 PSIG - DIFF SETPOINT +20 PSIG - DIFF SETPOINT +20 PSIG - DIFF Locations of the fans and a table showing the operation is shown in Fig. 35. YORK INTERNATIONAL 101

102 102 YORK INTERNATIONAL

103 FORM NM2 YORK INTERNATIONAL 103

104 Proud Sponsor of the 1996 U.S. Olympic Team 36USC380 P.O Box 1592, York, Pennsylvania USA Copyright by York International Corporation 1996 FORM NM1 (496) SUPERSEDES: NOTHING Subject to change without notice. Printed in USA ALL RIGHTS RESERVED