The Caleffi 535651HA 3/4-inch Pressure Reducing Valve is a brass plumbing control designed to regulate and stabilize incoming water pressure in residential and commercial hydronic heating systems. It automatically reduces excessive supply pressure to a preset level, helping protect boilers, piping, and connected equipment from pressure fluctuations. Featuring press connections, union ... https://www.partshnc.com/535651ha-caleffi-3-4-pressure-reducing-valve