Honeywell's most popuar Auto By-Pass Valve. 22mm Angle pattern. 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. particularly important when heating sustems contain large numbers of TRV's (Thermostatic Radiator valves. Building Regulations require bypass circuits to use Automatic Bypass valves and not fixed poistion valves.
