HONEYWELL 22mm Angled Automatic By-Pass Valve, DU145-3/4B

£34.50 inc. of VAT

£28.75 ex. of VAT

£43.44 RRP

21% Saving

MPN: DU145-3/4B


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HONEYWELL 22mm Angled Automatic By-Pass Valve DU145-3/4B for domestic heating systems.

HONEYWELL Angled Automatic By-Pass and Differential Pressure Valve is used to maintain a constant differential pressure in a heating system. It reduces flow noise in a system, particularly as thermostatic radiator valves are closed. The boiler return temperature is raised and this reduces corrosion caused by flue gas condensation. In addition, when radiator valves are closed, it also maintains flow over the temperature sensor on the boiler to ensure proper operation of external temperature compensation controls. On gas-fired water heaters it guarantees a minimum flow circulation when thermostats or radiator valves are closed.

Automatic By-Pass Valve is typically installed between the flow and return pipework near the boiler. Building regulations advise that if a by-pass is installed it should be an automatic type.


- Unique and simple adjustment mechanism.
- High capacity flow: Up to 50 ltrs/min.
- Wide differential pressure range: 0.1 to 0.6 bar.
- Standard 22mm compression fittings for ease of installation.
- Reduces system noise and maintains an even system pressure.
- Ensures constant flow through boiler.
- Lockable set pressure prevents inadvertent adjustment.
- Materials: Brass housing and fittings, plastic sping bonnet assembly and valve disc, stainless steel spring, EPDM seals.
- Max. temperature: 110°C.
- Max. operating pressure: 3 bar.