The Danfoss 020B1054 NRV 19s Check Valve is a refrigerant control component designed to ensure one-way refrigerant flow in HVAC and refrigeration systems. It automatically opens when pressure allows refrigerant to move in the intended direction and closes to prevent reverse flow. Featuring 7/8-inch ODF connections, this valve is suitable for air conditioning units, heat pumps, and com... https://www.partshnc.com/020b1054-danfoss-78-odf-nrv-19s-check-valve