Series 374A Boiler Pressure Relief Valves are used in hot water boiler applications to protect against excessive pressure on all types of hot water heating boiler equipment. It consists of an iron body construction with forged bronze inlet connections, non-metallic disc-to-metal seating, stainless steel spring, and test lever. Series 374A Pressure Relief Valves resist corrosive water conditions, sticking and freezing, and prevent water and sediment from being trapped in the seat. They is designed for emergency safety relief and shall not be used as an operating control.