The 3/4 in. Cast-Iron Water Pressure Safety relief valve is 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. 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 and not as an operating control.