The Altecnic Eres Straight Bypass Valve 22mm delivers precise differential pressure control for heating systems incorporating 2-port control valves and radiator circuits with thermostatic radiator valves. Engineered with compression ends complying with BS EN 1252-2 for use with R250 half-hard copper tube. Installed in the bypass between flow and return pipes, the valve opens on rising differential pressure, maintaining the predetermined set value between 1 to 6m head (10 to 60 kPa). The adjustable control knob allows precise pressure calibration. The stainless steel compression spring exerts a predetermined force onto the disc, ensuring reliable performance across constant and variable volume systems. A protective chrome dome conceals the scale and adjustment mechanism for clean installation aesthetics. Features & Benefits: Maintains differential pressure in variable flowrate heating systems preventing performance degradation of 2-port control valves. Adjustable differential pressure control from 1 to 6m head (10 to 60 kPa) via control knob. Stainless steel compression spring delivers reliable force application to disc mechanism. Compression ends comply with BS EN 1252-2 for use with R250 half-hard copper tube. Protective chrome dome conceals scale and adjustment mechanism for neat installation. Suitable for radiator circuits with thermostatic radiator valves, heating systems with 2-port control valves, and constant or variable volume applications. Size: 22mm.