The Honeywell Home V4073A Motorised 3 Port Mid Position Valve is designed to control water flow in domestic central heating systems where both radiator and hot water cylinder circuits are pumped. This 22mm valve is suitable for small to medium-sized installations and systems up to 90,000 Btu (26 kW). Key features include quiet operation, minimal power consumption, and a replaceable powerhead without draining the system. It also offers a potential-free end switch for electrical control of the pump and/or boiler. The valve opens to Port B in 8 seconds (under spring return) and comes with a 1m flying lead, head-resistant cable.