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Automatic bypass valve for hydronic heating systems, DU144

Automatic bypass valve for hydronic heating systems, DU144

The automatic bypass and differential pressure valve controls water flow in the heating circuit according to the water pressure across it and is used to maintain a minimum flow rate...

Product Description

The automatic bypass and differential pressure valve controls water flow in the heating circuit according to the water pressure across it and is used to maintain a minimum flow rate through the boiler and to limit circulation pressure when other water paths are closed. A bypass circuit must be installed if the Boiler manufacturer requires one, or specifies that a minimum flow rate has to be maintained whilst the Boiler is firing. The use of automatic bypass valves becomes particularly important when heating systems include large numbers of thermostatic radiator valves (TRVs) - whilst the TRVs are open the automatic bypass valve remains closed, however, as the TRVs start to close, the automatic bypass valve starts to open maintaining the required water flow through the boiler. Using an automatic bypass valve is also likely to reduce noise in systems caused by excess water velocities. It also helps to reduce the corrosion caused by flue gas condensation as the boiler return temperature is raised. 

Technical Properties

Medium type water or water-glycol mixture according to VDI 2035
Maximum operating pressure 10 bar
Differential pressure setpoint range 0,1 ... 0,6 bar
Media temp. 2 ... 110 oC
Kvs value 2,3
Materials
  • Valve housing, fittings, bonnet and handwheel made of brass
  • Spindle and spring made of stainless steel
  • All sealings made of EPDM and NBR
  • Protection cap made of red plastic
Additional description
  • Maintain minimum flow through a boiler
  • Minimises flow noise
  • Hinders boiler corrosion
  • Differential pressure finely adjustable using indicator scale
  • Presetting covered by a protection cap
  • No external controls required
pH-range 8 ... 9,5
Differential pressure setpoint fixed 0,2 bar

Продукти

Product Type Product description
DU144

DU144A1001
with compression fittings for 22mm copper pipe

DU144A1002
with 3/4" external threads

DU144A1003
with 3/4" internal threads