Abstract: A refrigerating circuit of an air conditioning apparatus has a refrigerating circuit which is formed with a compressor, an expansion valve, a first heat-exchanger and a second heat-exchanger. The amount of the refrigerant in the refrigerating circuit is controlled by the expansion valve which is controlled by a control unit. The control unit is provided with detector means including various sensors for detecting the ambient temperature, saturation temperature of the refrigerant in the refrigerating cycle, temperature of the discharged refrigerant fed from the compressor, etc. Detection of refrigerant leakage from the refrigerating circuit is accurately performed by the detector means. Control means responsive to the detector means controls the operation of the compressor. The compressor is stopped when the ambient temperature is within a pre-determined level and the discharged temperature exceeds a given level if the opening of the expansion valve is full. Malfunction of the compressor is thus prevented.

Abstract: A total cooling capability requested from one or a plurality of indoor units is compared with a total heating capability requested from one or the plurality of indoor units to set a cooling or heating operation mode.

Abstract: A total cooling capability requested from one or a plurality of indoor units is compared with a total heating capability requested from one or the plurality of indoor units to set a cooling or heating operation mode.