HYDRO MASTER 0571102 Safety Relief Valve 3/4" 150 PSI ASME

Safety Relief Valve 150 PSI

The HYDRO MASTER 0571102 is a brass safety relief valve built for residential hot-water systems. It opens automatically when pressure exceeds 150 PSI to protect tanks and piping from over-pressure caused by thermal expansion. The ASME rating of 500000 BTU/hr confirms it meets code requirements for standard water-heater installations. Installers and homeowners use it on 3/4-inch NPT connections throughout U.S. plumbing.

3/4-Inch MNPT x FNPT Connection

The valve features a 3/4-inch male NPT inlet that threads directly into a female NPT port per ANSI/ASME B1.20.1. An integrated full-port ball valve and a brass-capped drain valve sit on the outlet side for maintenance access. All wetted parts are brass with a stainless-steel spring, so no dissimilar metals contact the water. This single connection pattern determines whether the valve fits the existing heater or storage tank.

Sustained Over-Pressure Relief

Under continuous thermal expansion the valve lifts at the 150 PSI set point and discharges water through the full-port ball valve until system pressure drops below the reseat pressure. The stainless-steel spring maintains consistent opening force over repeated cycles without fatigue. The brass cap on the drain port prevents debris entry while allowing periodic manual testing. The assembly is designed for long-term pressure protection rather than emergency burst relief.