HONEYWELL D146M1040 Differential Pressure Regulator. Used to eliminate excessive pump head pressure when most radiator valves are closed due to reduced demand.
â€¢Â Flow through the system is reduced
â€¢Â Simple installation, requires no electric hookup
â€¢Â Desired pressure is set by turning the regulating handle
â€¢Â Valve Bonnet and body are brass