An apparatus comprising: a suction header configured to receive a refrigerant; a compressor configured to compress the refrigerant from the suction header; a drain leg coupled to the suction header through a first line; a drain valve provided on said first line for controlling the flow of refrigerant and oil from the suction header to the drain leg; an oil separator connected to the compressor and configured to separate an oil from the refrigerant from the compressor; an oil reservoir connected to the oil separator; a second line connecting the drain leg and the oil reservoir; a check valve installed on the second line for controlling the flow of oil from the drain leg to the oil reservoir; a third line connecting the oil separator and the drain leg; and a valve provided on the third line for controlling the flow of oil from the oil separator to the drain leg, wherein, during a first mode of operation: the drain leg configured to collect an oil from the refrigerant at the suction header; and the oil separator configured to collect the oil separated from the refrigerant; and during a second mode of operation: the oil separator configured to direct the oil separated from the refrigerant from the compressor to the drain leg; and the drain leg configured to direct the oil from the oil separator and the oil collected from the refrigerant at the suction header to the oil reservoir. a suction header configured to receive a refrigerant; a compressor configured to compress the refrigerant from the suction header; a drain leg coupled to the suction header through a first line; a drain valve provided on said first line for controlling the flow of refrigerant and oil from the suction header to the drain leg; an oil separator connected to the compressor and configured to separate an oil from the refrigerant from the compressor; an oil reservoir connected to the oil separator; a second line connecting the drain leg and the oil reservoir; a check valve installed on the second line for controlling the flow of oil from the drain leg to the oil reservoir; a third line connecting the oil separator and the drain leg; and a valve provided on the third line for controlling the flow of oil from the oil separator to the drain leg, wherein, during a first mode of operation: the drain leg configured to collect an oil from the refrigerant at the suction header; and the oil separator configured to collect the oil separated from the refrigerant; and the drain leg configured to collect an oil from the refrigerant at the suction header; and the oil separator configured to collect the oil separated from the refrigerant; and during a second mode of operation: the oil separator configured to direct the oil separated from the refrigerant from the compressor to the drain leg; and the drain leg configured to direct the oil from the oil separator and the oil collected from the refrigerant at the suction header to the oil reservoir. the oil separator configured to direct the oil separated from the refrigerant from the compressor to the drain leg; and the drain leg configured to direct the oil from the oil separator and the oil collected from the refrigerant at the suction header to the oil reservoir.