Abstract: The present disclosure relates to retrofit for fan control in refrigerated cases. In exemplary embodiments, a system includes a leak sensor module for sensing leaked refrigerant and a universal connector. The universal connector is configured as a junction for connecting an AC voltage source with the evaporator fan and the leak sensor module. The universal connector is configured to be operable for selectively supplying AC voltage from the AC voltage source to the evaporator fan, or to the leak sensor module, or to both the evaporator fan and the leak sensor module. The system is configured such that when the leak sensor module is activated to conduct leak testing, the AC voltage from the AC voltage source to the evaporator fan is interrupted by the universal connector to thereby turn OFF the evaporator fan and facilitate detection of any leaked refrigerant.

Abstract: Systems and methods for purging lubricant from a first compressor to a second compressor are provided. A control module receives a lubricant purge command, shuts the second compressor to an OFF-mode while the first compressor remains in the ON-mode, restricts working fluid from an outlet of the second compressor from flowing into the first compressor and allows compressed working fluid discharged from an outlet of the first compressor to flow into the inlet of the second compressor such that lubricant in the second compressor flows into the first compressor.

Abstract: Systems and methods for purging lubricant from a first compressor to a second compressor are provided. A control module receives a lubricant purge command, shuts the second compressor to an OFF-mode while the first compressor remains in the ON-mode, restricts working fluid from an outlet of the second compressor from flowing into the first compressor and allows compressed working fluid discharged from an outlet of the first compressor to flow into the inlet of the second compressor such that lubricant in the second compressor flows into the first compressor.