The Resideo FM911 Backflow Preventer Pressure Reducing Valve is an essential component for safe and efficient hot water systems. This valve, with a 1/2" NPT/Sweat connection, is suitable for a variety of HVAC and plumbing applications. It guarantees that the water pressure does not exceed 12 PSI, preventing overpressure and potential damage. https://www.partshnc.com/fm911-resideo-12-redvlv12wbackflownptsw