The Potterton automatic air vent is a protection device within the central heating unit. It works by using floatation to release an accumulation of air. As water flows through the heating and cooling system, a float within the automatic air vent opens or closes depending on the water level. If the system contains no air, the float will be pushed to the top and the vent will be closed until the water level drops.
The automatic air vent fits in the top of the boiler
Technical specification
Waist Sizeaa42cb38fxTypeAutomatic Air VentSupplier Part Number5122330Brand NamePotterton