Kabushiki Kaisha Toshiba

Hirokazu Unno

Masahiko Otori

Shotaro Hamamoto

Nobusuke Shirakawa

The air conditioning apparatus operable in heating and cooling operation modes for air conditioning a room has an external unit, an inner unit, and a control device. The external unit includes an external heat exchanger. The inner unit disposed in the room includes an inner heat exchanger which functions as an evaporator in the cooling operation mode whereas the external heat exchanger functions as a condenser. The control device has a thermistor disposed on the inner heat exchangers for detecting temperature of the inner heat exchanger, bias means for energizing the thermistor with a predetermined bias potential and term setting means responsive to the operation mode for setting first and second terms for allowing The energization of the thermistor. The the first term is longer than the second term when the inner heat exchanger functions as an evaporator. The control device also has a room temperature sensor disposed in the room for detecting room temperature. The thermistor is tentatively energizing in order to detect temperature of the inner heat exchanger when a predetermined period of non-air conditioning operation has elapsed. Both detected temperatures in the non-air conditioning operation period are compared with each other. Malfunction of the thermistor or the room sensor is detected when the difference between two temperatures exceeds a predetermined value.

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Shizuoka, Japan

Hirokazu Unno