Product Information: The automatic air vent is a pressure safeguard in the central heating unit. They work by using a floatation device to release built up air. As water flows through the heating/cooling system, a float within the automatic air vent opens or closes depending on the water level. If the system is full of water, the float will be pushed to the top and the vent will be closed until the water level drops.
This part is present in 12 different boilers in the Glowworm range including the Glowworm SI 18 , SI 30 , SXI 18 , SXI 30 , CXI 24 .