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 . <EOS>