A system for cooling or heating a body part includes at least one bladder, a pump, a heat exchanger, a first fluid line in fluid communication with the heat exchanger and the at least one bladder, a second fluid line in fluid communication with the at least one bladder and the heat exchanger, a main reservoir and a separator. The heat exchanger is in fluid communication with the pump. The first fluid line is located downstream from the heat exchanger and the second fluid line is located downstream from the at least one bladder when the system is operating to cool or heat the body part. The separator is in fluid communication with the main reservoir and the pump and is located below the main reservoir to receive fluid under the influence of gravity from the main reservoir and to deliver fluid to the pump via gravity.
