| 摘要 |
PURPOSE:To prevent wasteful defrosting operation by performing a control to start defrosting operation only when defrosting requirement is still left after a blower on the side of an evaporator is put into operation for a fixed time during the overload protecting operation. CONSTITUTION:Heat absorption is promoted from the outside air with the operation of a blower 10 on the side of an evaporator and the temperature of the evaporator 5 rises. Under such a operation, as the temperature of a refrigerant is high on the side of a condenser 4, with the restarted operation of the ordinary blower 10, the temperature of the evaporator 5 rises to remove the frost immediately. Subsequently, the intermittent operation of the blower 10 is continued until overload is dissolved. But only when a detection means 19 still detects the defrosting requirement after the time t3 is reached with the passage of a certain time TM following the restart of the blower 10, a blower relay 22 is switched over to the stop position while a four-way valve relay 23 to the cooling cycle position and a defrosting operation is performed for a fixed time up to the time t4. Thus, the temperature of a heat exchanger 4 lowers while the temperature of a heat exchanger 5 rises to eliminate the overload state and the defrosting requirement as well and after the time t4, the heating operation is done again.
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