Series FV-4 Automatic Vent Valves are used in commercial and residential hydronic heating applications to provide automatic air venting for hot or cold water distribution systems. It consists of a brass body construction with female NPT connection, brass cover, air vent with silicone rubber seal, polyethylene float with valve plug, and automatic vent. Series FV-4M1 has a high temperature rating and is ideal for use with glycol systems or for use as an anti-vacuum device. It can also be installed to permit the separation and dispersal of air while fluid is circulating in the system. Can be disassembled for inspection and cleaning. Maximum Pressure: 150psi