Honeywell Home 22mm Automatic By-pass Valve Straight DU144

The Honeywell Home DU144 straight automatic bypass valve controls the water flow in the heating circuit, to maintain a minimum flow rate while the boiler is fired. The boiler return temperature is raised and this reduces the 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 compensating controls. On gas fired water heaters it guarantees a minimum flow circulation when thermostats or radiator valves are closed.