Danfoss KDC 65 A 3 multifunctional compressor valve (pressure control valve), code 148G3811. Angle-way valve with butt-weld connections to ASME B36.10M Schedule 40, nominal size 65 mm (2 1/2 in), for industrial refrigeration compressor packages. The KDC controls the compressor discharge pressure to ensure a fast build-up of pressure and lubrication (oil) pressure at start-up, and simultaneously acts as a check valve in the compressor discharge line to prevent reverse flow when the compressor stops. The valve is force-controlled: it opens when the pressure downstream (oil separator / discharge side) rises to 3 bar (43.5 psi) above the suction pressure, at which point the spring is compressed and the cone lifts. This 3 bar spring setting suits high-pressure compressors. Housing and bonnet are low-temperature steel with stainless-steel bolts; the valve is mounted vertically with the cone downward and carries a threaded NPT 1/4 in pilot-line connection on the bonnet. Maximum working pressure 40 bar (580 psig); media temperature range -50 °C to 150 °C (-58 °F to 302 °F). Flow coefficient Kv 78 m³/h fully open. CE marked.