Honeywell 22mm Straight Automatic Bypass Valve DU144

The DU144 Automatic Bypass Valve controls the flow of water through a bypass circuit which is installed between flow and return pipework, typically at or near the boiler. Building Regulations advice states that if a bypass is installed, an automatic bypass valve must be fitted.

The DU144 saves energy by only allowing flow through the bypass when needed i.e. when flow through the system is reduced when zone valves or radiator thermostats are closing. The use of an ABV is recommended by the UK Government as Best Practice in the CHeSS (Central Heating System Specifications) guide to central heating systems.