Patent ID: 6910341

Claim:
A method of operating a temperature control unit, the temperature control unit including a refrigeration circuit housing a refrigerant and having a compressor, a condenser, and an evaporator coil, the method comprising: providing a first flow path extending through the compressor, the condenser, and the evaporator: providing a second flow path extending through the compressor and the evaporator, the second flow path bypassing a section of the refrigeration circuit; directing refrigerant through the first flow path during operation in a cooling mode; directing refrigerant through the second flow path during operation in a heating mode; and recovering refrigerant from the section of the refrigeration circuit during operation in a recovery cycle; wherein the temperature control unit defines an air inlet and an air outlet and the method further comprises: providing an efficiency range; measuring an air inlet temperature; measuring an air outlet temperature; calculating a temperature change between the air inlet temperature and the air outlet temperature; and initiating the recovery cycle when the temperature change is outside the efficiency range.