Danfoss KDC 125 D 0.5 multifunctional compressor valve (pressure control valve), code 148G3597. Angle-way valve with butt-weld connections to EN 10220, nominal size 125 mm (5 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 0.5 bar (7.5 psi) above the suction pressure, at which point the spring is compressed and the cone lifts. This 0.5 bar spring setting suits low-pressure (booster) compressors, which require only a small differential to open. 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 333 m³/h (Cv 386 gal/min) fully open. Suitable for HCFC / HFC, R717 (ammonia) and R744 (CO2) refrigerants. PED category III. CE marked.