Danfoss NRVA 40 check valve (non-return valve) for industrial refrigeration, OEM P/N 020-2004. Prevents reverse flow of refrigerant in liquid, suction and hot-gas lines of ammonia (R717), HCFC and HFC plant. Butt-weld connection 40 mm (1 1/2 in) to EN 10220 (ANSI B 36.10 pipe schedules). Fitted with a damping piston, so it is suited to pulsating lines such as the compressor discharge line, and a PTFE valve seat for tight seating with minimum closing force. No orientation limitation. Max working pressure 40 bar (580 psig); media temperature -50 °C to 140 °C. NRVA = standard spring; a stronger spring is available for special duties (see ordering table). Verify refrigerant compatibility against the datasheet.