The Brass Bottle Air Vent has a 1/2'' male thread and is used at high points in the pipe work of a heating system to remove air and expansion gases which cannot be removed through normal venting processes. As water fills the system air will escape through the air vent. When the water level reaches the vent it forces the internal float upwards which shuts the vent and importantly prevents any water from escaping. As any air or gases accumulate in the water system there-after the float will drop and air will automatically be aloud pass out through the vent once again.
Automatic air vent
1/2" male thread
Rubber seal on male thread of vent