Due to system design, loads & defrost cycles, varying amounts of oil can be returned by the oil separator. Because of this, a safety reserve of oil is required for the operation of our oil control system, The oil receiver is the holding vessel for this stand-by oil. It has sight glass ports to observe the oil level inside the vessel. The valve on top of the oil receiver receives oil form the oil separator, and the bottom valve distributes oil to the oil level  regulator. The valves are back seating and have a 1/4” SAE connection, allowing the addition or removal of oil from the receiver. High pressure gas returns with the oil from the oil separator to the oil receiver. Pressure could be increase in the oil receiver to adversely affect the receiver regulators. To prevent this, a vent line is installed from the top the oil receiver to the suction line, This line permits the pressure in the oil receiver to be approximately the same as suction line and the compressor crankcase.