Caleffi 5080 Hygroscopic Automatic/Manual Compact Air Vent With Service Check Valve, 1/8 in, MNPT, 150 psi Working 212 deg F, Brass, 11/16 in Dia x 1-1/4 in H, Import
The purpose of the radiator air vent valve is to remove, either manually or automatically, any air trapped inside the heat emitters both during the filling of the system and in normal operation. The drain valve, on the other hand, makes it possible to easily discharge the water contained in the radiator, thanks to the extractor which is inserted into the valve itself.