| 摘要 |
PROBLEM TO BE SOLVED: To minimize radiation loss due to defrost of an outdoor unit by prohibiting defrost even when the temperature drops below a defrost starting temperature during defrost operation of an outdoor heat exchanger so long as the temperature detected at a room temperature sensor section is higher than the sum of a set temperature and a specified temperature. SOLUTION: At the time of heating operation, an outdoor heat exchange temperature comparing section 4a at an outdoor unit control section 4 makes a decision whether the temperature detected at an outdoor heat sensor section 9 arranged on the piping of an outdoor heat exchange has dropped below a defrost starting temperature or not. If it has dropped below the defrost starting temperature, a decision is made whether the temperature detected at a room temperature sensor section 16 is higher than the sum of a set temperature and a specified temperature. Defrost is started it the answer is Yes, otherwise a new defrost starting temperature is set by subtracting a specified value from current defrost starting temperature and stored in a memory 14. Since the specified value is decreased sequentially, an optimal defrost timing can be attained. |
