By-pass valves Series 466 Thermatic - Series USVR Main features - Available in the following version : Female/Female series 466 1/2, 3/4, 1 Female/Male series USVR 3/4, 1, 1.1/4 - Conforms to standard: UNI 9335/61 - D.M. 1/12/1975 Body R Cap.R.2.A.2
2 Description By-pass valves series 466 Thermatic and series USVR are devices for differential pressure control between two points of a circuit, designed in order to overcome the problems of variable flow rate plants and guarantee the by-pass which is proportional to the difference between the nominal pump head and the working conditions. 466 THERMATIC. Relief valve for systems with automatic or manual shut-off elements on the radiators (thermostatic valves, two-way zone valves). Brass CW617N body and ABS cap. Nominal pressure : NP 10. Overpressure : 10-15%. Max operating temperature : 110 C. Type Part number Size body bar Flow rate (l/h) Weight (g) 466 4660C12 1/2" FF 0,05-0,7 1750 630 466 4661C34 3/4" FF 0,05-0,7 3500 850 466 4662C1 1" FF 0,05-0,7 7000 1180 USVR Relief valve for systems with automatic or manual shut-off elements on the radiators (thermostatic valves, two-way zone valves). Female inlet connections, Male union outlet. Body and cap of brass CW617N. Adjustment : Position 0 = Fully open - Position 7 = Close to closing Δp =0.5 bar Plastic knob. Max operating pressure : 6 bar. Overpressure : 10-15%. Max operating temperature : 110 C Type Part number Size body bar Flow rate (l/h) Weight (g) USVR 0265216 3/4" FM 0,06-0,36 3000 400 USVR 0265220 3/4" FM 0,03-0,50 3000 500 USVR 0265225 1" FM 0,03-0,55 5700 900 USVR 0265232 1.1/4" FM 0,06-0,46 12000 1050 Application By-pass valves series 466 and USVR are used in all heating systems in which the heating units are provided with thermostatic valves, zone valves or electrothermic valves series 22C. The above mentioned regulation systems, control the room temperature adjusting the flow rate in the heating units. When thermostatic or electrothermic valves close could create noise problems and high differential pressure values on the opened valves of the circuit. This forces the pump to work continually in variable conditions reaching important differences from the initial pump head. The fitting of the by-pass valves between the delivery and the return side of every load line enables resonably costant discharge to be maintained. Operation The By-Pass valve will open assuring a constant water flow through the heat generator (very important for gas boiler) and increasing the return temperature to the heat generator (anti corrosion function). The reliability of the pressure relief valve series 466 or USVR are factory controlled on 100% of the production. Choice To choise the valve it usually has to be considering a 25-30% by-pass of the overall flow rate of the circuit to be protected and an overpressure of about 10-15% of the head in that particular point of the circuit. Whenever no particular datas are evailable select the most appropiate model considering the overall flow rate : up to 1750 l/hour Art 4660C up to 3500 l/hour Art 4661C up to 7000 l/hour Art 4662C Set the max working pressure value during the plant testing stage.
Exemple with valve series 466 Circuit overall flow rate: 2000 l/hour Head in the safety valve installation point: 4 m ( 0.4 bar ) Max. overpressure 0.5 m ( 0.05 bar ) Results : By-pass flow rate: 600 l/hour Max pressure 0.4 bar Max pressure with by-pass of 600 l/hour: 0.4 + 0.05 = 0.45 bar The most appropriate choice is the 4661C model which by-passes 800 l/hour in correspondence of a pressure variation from 0.4 to 0.45 bar (the 4660C model by-passes only 500 l/hour). Setting By-pass valve series 466 can be adjusted in two ways : Using the pump flow rate and valve diagrams. For example, using a pump with a flow rate of 2000 litres per hour and a head of 0.4 bar, a 3/4 Thermatic would be suitable. Follow the red curve downward from the point on the 3/4 graph where the 2000 l/h line and the 0,4 bar line meet. The left hand end of the red line shows the valve setting recommended, i.e 0,3 bar. When installing by-pass valve in a system where the flow rate of the pump is not know, the valve can be adjusted by checking the pump head with pressure gauge. Alternatively, it can be set by gradual adjustment of the valve until silent running and low over-pressure are achieved. Once the correct setting is established, it can be fixed with the locking screw of the handwheel. By-pass valve series USVR can be set in this way: Thighten blocking screw (1) (see overall dimensions). Set the USVR valve at the differential opening pressure ΔP by turning regulation knob (2) (see overall dimensions). The differential opening pressure DP shall exceed the user circuit load loss at rated discharge by approximately 20% in order that avoid valve opening be prevented. When the user circuits is completely closed, the USVR valve shall be fully open. Turn regulation knob anticlockwise untilscale (3) (see overall dimensions) indicates zero. Then proceed, turning clockwise, to calibration setting at the number required. Each number from 0-7 revers to an USVR16 - USVR20 USVR25 - USVR32. Once the correct setting is established, it can be fixed with the locking screw of the handwheel (1). Installation By-pass valves series 466 or USVR should be installed after circulating pumps between the supply main and the return main (see scheme). Mounting the by-pass valves do not operate with the spanner on the upper hexagonal part of the valves. Art 148 Art 22C Technical characteristics Max operating pressure 466 10 bar Max operating pressure USVR 6 bar Overpressure 10 15% Max operating temperature 110 C Design features Body valves Brass CW617N Setting sprins Stainless UNI 3823 Plug Alluminium BT3 UNI 6362 O-ring EPDM Cap ABS
Pressure drop charts 4660 1/2" 4661 3/4" 4 4662 1"
USVR16 3/4" 5 USVR20 3/4" USVR25 1"
USVR32 1.1/4" 6 Overall dimensions (mm) USVR 1 C 466 2 3 B A B A C A B C 3/4 23 88 62.5 3/4 26 120 70 1 33 138 83.5 1.1/4 39 148 100 A B C 1/2 135 32 36 3/4 141 35 41 1 195 41 46 Re-order no. 54-0040-UK-IT/1-06-06-Rev.0 The descriptions and photographs contained in this brochure are supplied by way of information only and are not binding. Watts Industries reserves the right to carry out any technical and aesthetic modifications to its products without prior notice. Watts Industries Italia s.r.l. Via Brenno, 21-20046 Biassono (MI), Italy Ph. : +39 039 49.86.1 - Fax : +39 039 49.86.222 e-mail : info@wattsindustries.it www.wattsindustries.com