STA STM Typ STA 5936 Typ STM 5937 GB Installation and operating instructions 1999,
2
Contents GB UK Limited P.O. Box 9, Washway Lane, St. Helens, Merseyside WA10 6FE United Kingdom Telephone: 01744 744744 Fax: 01744 744700 Chapter Page 1. General 3 2. Construction 4 3. Operation 4 4. Technical data 5 5. Placing and installation 5 6. Adjustment and commissioning 7 7. Maintenance and inspection 8 1. General The monitors the content in closed water central heating and cooling installations and makes up water loss as necessary. The make-up is done on the basis of pressure or level in an adjustable time interval. The prevents the ingress of air and the associated operational failure, and corrosion in the installation. With the use of the, there is no further requirement for manual make-up or the associated venting. The construction of the fulfils the requirements of DIN 1988. Fields of application type STA - for installations with pump- or compressor-controlled diaphragm expansion automats (including Flexcon M-K and Flexcon M-P), where the make-up pressure is at least 1.2 bar less than the pressure of the mains water supply. type STM - for installations with standard diaphragm expansion vessels with fixed fill pressure (including Flexcon M, Flexcon B, Pro-Flex, Flexcon and Contra-Flex), where the make-up pressure is at least 1.3 bar less than the pressure of the mains water supply. Note In installations where the individual pressure differences (pressure of the mains water supply - make-up pressure < 1.2 or 1.3 bar) do not allow the application of a type STA or type STM, pump-controlled make-up automats of the types PA or PM can be used. The is not to be used for a first or new filling! For UK installations, refer to UK Limited for special units to comply with Local Regulations. 3
2. Construction The types STA and STM consist of the following main parts: - hydraulic part - control - housing - pressure switch (only STM) type STA A. ball valve B. water meter C. strainer D. system separator (DVGW tested) E. solenoid valve F. control with indication fault signal display G. cable inlet and outlet 6034 Separate illustrations of the operating panel of the controls. 60 60 30 90 30 90 0 120 running time fuse in minutes defective water shortage fault fault remove ON/OFF type STA 0 120 running time fuse in minutes defective water shortage fault fault remove ON/OFF type STM 3. Operation 6033 6033 type STA - the control is activated by an external potential-free signal from the control of a pump- or compressor-controlled diaphragm expansion automat. - the solenoid valve is opened by the signal and water in the installation is made up until the pre-set level value on the control of the expansion automat is reached. type STM - the control is activated by a pressure switch with a fixed pressure difference (this pressure switch is part of the unit). - when the pressure in the installation falls to the pre-set value on the pressure switch, the solenoid valve is opened and water is made up until the switching differential that is set on the pressure switch is reached. If the make-up time that is set on the control is exceeded (this setting is specific for the installation), the solenoid valve is closed and the "fault" LED lights. The make-up installation is cut out, and can only be reset by pressing the "remove fault" pushbutton. It is recommended to check the installation first for leakages. If a fault occurs in the drinking water supply, the protection against running dry is activated, the "water shortage" LED is lit and the pump is switched off. If the "fuse defective" LED lights, a fault on the solenoid valve has activated a fuse. Please contact our customer service. 4
4. Technical data ➂ L D W ➁ ➀ ➀ water mains connection ➁ system connection ➂ drain connection of system separator 6132 General - max. supply pressure : 10 bar - max. operating temperature : 40 C - max. volume flow : 2.3 m 3 /h - max. adjustable make-up time : 120 min - mains voltage : 230 V/50 Hz - mains fuses : 250 V/6 A - secondary-side load fuse : 250 V/1.8 A (slow) - max. current for fault signal : 250 V/5 A AC - supply pipe-work connection : 1 /2 (inner screwthread) - system connection : 1 /2 (outer screwthread) - overflow connection : DN 40 (HT pipe) - dimensions : L x W x D = 600 x 200 x 120 mm Special for STA - minimum pressure difference between mains water pressure and system pressure: 1.2 bar - weight: 11 kg Special for STM - minimum pressure difference between mains water pressure and system pressure or selected switch-on pressure of the make-up: 1.3 bar - adjustment range of pressure switch: 0.5 to 6 bar - switching differential of the pressure switch: 0.3 bar - weight: 12 kg 5. Placing and installation The may only be installed in a frost-free area! First, the appropriate wall fixtures must be mounted on the wall. Then, the is aligned and mounted, whereby care must be taken that there is sufficient free space at the side for the hydraulic connections. All connections must be made according to locally applicable rules! Hydraulic connections The internal ball valves (item A on page 4) must be closed! First, the mains supply pipework and the system connection must be sealed. Before doing this, the mains supply pipe-work should be completely flushed out. After the appropriate drainage funnel of the system separator is attached, the drainage pipe-work (HT pipe DN 40) is fitted on site. With the STM, the appropriate pressure switch (connection 1 /2 AG) must be so installed that there can be no dynamic effects in operation (for example in the expansion pipe-work)! 5
Electrical connections The is wired in the factory. The abbreviations on the terminal block of the control have the following significance: wiring in the factory at installation PE earthing of solenoid valve and robust casing x PE earthing conductor of mains x N neutral conductor of mains x L live conductor of mains x S1 on and off switch of connection 1 x S1a on and off switch of connection 1a x S1b on and off switch of connection 1b x P/M solenoid valve connection x P/M solenoid valve connection x O fault signal - NC (break) x G fault signal - COMM (common) x S fault signal - NO (make) x E1b connection to potential-free input signal x E1a connection to potential-free input signal x E2b spare E2a spare A Schuko wall socket must be installed for the connection to the mains. The mains cable (length 2 m) that is connected to the control is fed through the cable grommet (see item G on page 4) and connected to the Schuko plug which is supplied with the installation. A possible alternative is a connection on the junction box. Special for STA The electrical connection to the expansion automat is made at installation with a 2-way cable with a cross-section of at least 2 x 0.75 mm 2. The connection to the control of the is made on the E1a and E1b terminals. For this purpose, the control must be removed by unscrewing both cylinder screws from the robust casing. Next, the control housing is screwed back on the front. The cable is fed through the cable grommet in the robust casing and fed through the PG screw connection in the control cabinet and connected. Now, the control is replaced in the reverse order to removal. The connection to the expansion automat is done according to the installation specification of the expansion automat. Special for STM The electrical connection to the pressure switch is made with a 2-way cable (length 4 m) that is connected to the control and fed through the cable grommet from the robust casing to terminals 1 and 2 of the Hirschmann plug of the pressure switch, where it is inserted and screwed tight. If necessary, the cable (cross-section of at least 2 x 0.75 mm 2 ) can be extended or shortened on installation. There is a potential-free change-over contact available for the telemetry fault signal, so that a suitable signal processing can be made on installation (make or break contact). The connection to the control is done as previously described. 6
Steuerautomat Examples of installations 1. STA in an installation with Flexcon M-P 6036 FLEXCON M - P expansion pipe-work 2. STM in an installation with Flexcon M 6037 FLEXCON M P expansion pipe-work 6. Adjustment and commissioning Following the inspection of all connections, the ball valves are slowly opened (first at the supply) and the robust casing is closed. Special for STA The differential pressure present is determined on the basis of the supply and system pressures. With this value, the make-up rate is read from the graph on page 8. The percentage values for switching the make-up installation on and off that are set on the control of the expansion automat are the basis for the calculation of the make-up volume. The division of the two values, increased by 10 minutes, gives the make-up time that must be set. Example: Supply pressure : 6 bar System pressure : 2 bar Expansion automat : Flexcon M-P 5000 Switch-on value of make-up : 07 % Switch-off value of make-up : 15 % Difference pressure : 4 bar Determined make-up requirement : 1450 l/h, or 24.167 l/min Determined make-up volume : 8 % of 5000 l = 400 l Make-up time that must be set 400 l : 24.167 l/min + 10 min = 27 min 7
Special for STM The switch-on pressure must be chosen slightly higher than the starting pressure of the expansion vessel. The difference of the mains supply pressure and the switch-on pressure increased by half the switching difference of the pressure switch (0.15 bar) gives the average differential pressure. The theoretically possible make-up volume is calculated on the basis of the vessel and expansion vessel volume and the pressure factor (values from design data). The division of the two values, increased by 10 minutes, again gives the make-up time that must be set. Example: Mains pressure : 5 bar Expansion vessel : Flexcon M 1200-5 bar Starting pressure : 1 bar Switch-on value of make-up : 1.1 bar Expansion volume : 600 l Pressure factor : 0.64 Average pressure difference : 3.75 bar Determined make-up rate : 1400 l/h, or 23.33 l/min Determined make-up volume : 1200 l x 0.64-600 l = 168 l Make-up time that must be set : 168 l + 10 min = 17 min 23.33 l/min After setting the make-up time, with the type STM, the switch-on pressure of the pressure switch is also set. For this purpose, the black knurled nut on the top of the pressure switch is pulled off and replaced upside down. The switch-on pressure corresponds with the top of the needle. Next, the pressure switch is again pulled off and placed upside down. Now, the can be put into operation by switching the main switch on. Graph of the STA and STM make-up rate (small, system-specific deviations are possible). 2500 Make-up rate in l/h 2000 1500 1000 500 1 2 3 4 5 6 7 Difference pressure (STA) or average difference pressure (STM) in bar 7. Maintenance and inspection The sieve of the strainer (item C on page 4) must be cleaned once per year. The rest of the components do not require any maintenance. Every six months, the system separator (item D on page 4) must be tested by the operator or installation contractor, according to DIN 1988, Part 8. For this purpose, the ball valves on the output side and input side are slowly closed after each other. The pressure difference measured on the test ball valves between the front and middle chambers must be 0.2 bar and must be maintained. 6035 8