The Conbraco Industries 10-417-15 Water Relief Valve 3/4" x 3/4", 972,000 BTU, 75 PSI is a durable safety component designed to protect HVAC and hydronic systems from excessive pressure. It functions by automatically discharging water when system pressure rises above the 75-psi limit, ensuring stable and safe operation. https://www.partshnc.com/10-417-15-conbraco-industries-34-x34-h2o-75rlf-972000