Reliance Valves 2 Port Zone Valves are designed for use in heating systems to isolate zones or equipment when the motor within the zone valve is de-energised. The valve can shut off water flow or control and regulate water flow through domestic and light commercial central heating systems.Designed with an easy to use clip-on detachable head, pre-moulded plug and play cables and a metal manual operating lever, the 2 Port Zone Valve is durable and quick and easy to install to new systems or retrofit to existing systems.