The Watts 740-2-40 Pressure Relief Valve is a safety component designed to protect compatible hydronic heating systems and boilers from excessive pressure. It automatically opens when system pressure reaches its preset limit, releasing excess fluid to help prevent equipment damage and maintain safe operating conditions. This valve supports reliable pressure management in residential a... https://www.partshnc.com/740-2-40-watts-relief-valve-2-x-2-12-40-psi-6440m-btu-f384240-used-to-be-0384240