This boiler pressure relief valve is used in hot water heating and domestic supply boiler applications to protect against excessive pressures on all types of hot water heating supply boiler equipment. It consists of a brass body construction with NPT threaded male inlet and NPT threaded female outlet connections, non-metallic disc-to-metal seating, stainless steel spring, and test lever. It resists corrosive water conditions, sticking and freezing, and prevents water and sediment from being trapped in the seat. It is designed for emergency safety relief, not as an operating control. The standard pressure setting is 75 psi (517 kPa) and is rated to 738,000 BTU/hr.