Three function Double Orifice Air Valve with stop valve
Double orifice Air Valve that combines both l orifice functions within one unit. Air is vented from the system until water enters the valve and lifts the float against its seat, ensuring a tight seal. In the event of sub-atmospheric pressure in the system, the water level drops causing the float to fall from its seat and allow the admission of air.
During normal working of the main the small orifice releases the air which accumulates under pressure. With the main in operation, the float is normally against its seat. As air enters the chamber body the water level is depressed until a level is reached when the float drops from its seat, which allows air to escape. The consequent rise in water level returns the float to its seat.