The Watts Series FV-4M1 Automatic Air Vent Valves provide automatic air venting for hot hydronic heating or cold water distribution systems. These vents purge air that may be in the water system.
The Watts FV4M1 Auto Vent utilizes a float to actuate the valve plug which is located at the top of the valve. Once the air is displaced and the system pressure is sustained the valve plug seals and prevents any water from escaping from the system.
The float vent can also operate as an anti-vacuum device since
it will permit air to enter the system when it must be drained. It can also be installed to permit the separation and dispersal of air while fluid is actually circulating in the system.
External link | Downloadable Files
WATTS REGULATOR web site
Product Spec Sheet