The Halstead gas valve is a special mechanical device which is designed to control the pressure and flow of gas to the valve. This is a mechanism that controls the flow of gas to the burner. Depending on the model of your boiler, it is controlled by an electrical signal coming from the Printed Circuit Board (PCB).
Comes with screws and a shaped gasket
Technical specification
TypeFull Gas ValveSupplier Part Number988315Brand NameHalstead