Abstract: A system for a cooler comprises: a heat exchange tube receiving a supply of pressurized gas, a gas escape aperture communicating with the interior of the heat exchange tube for permitting escape of the pressurized gas and expansion thereof during cooling mode, and a bypass assembly associated with said heat exchange tube and located after said gas escape aperture which during a cleaning mode enables most of the pressurized gas to exit the heat exchange tube without flowing through said gas escape aperture. The bypass assembly comprises a flush valve which is closed during said cooling mode and which is opened during said cleaning mode. According to a preferred embodiment, the heat exchange tube is helically wound over a cylindrical core and installed inside an insulated housing. The system may also be utilized as a gas purity tester, optionally with an additional gas pressure regulator, wherein a sensor will indicate the extent of the gas purity.