The HTP 7250P-080 Pressure Relief Valve is a 3/4-inch MNPT x FNPT safety valve designed to protect hydronic heating equipment from excessive pressure. It automatically opens when system pressure exceeds its 30 psi setting, releasing excess water to help prevent equipment damage and unsafe pressure buildup. This bronze valve is rated for systems up to 510,000 BTU/hr and is used with HT... https://www.partshnc.com/htp-7250p-080-pressure-relief-valve-3-4-mnpt-x-fnpt