| 摘要 |
PURPOSE:To prevent shortage in the lubrication of a circulating oil due to the lowering of the suction pressure and to eliminate any trouble of seizure of a cylinder during a defrosting operation by once stopping a compressor when the operational mode enters a defrosting operation from the space heating operation, and starting the defrosting operation after averaging the discharge pressure and the suction pressure. CONSTITUTION:When the operational mode is going to be changed over to a defrosting operation 32 from a space heating operation 30, the excitation of a four-way valve 2 is removed and a compressor 1 is once stopped. This stopping time is set by a timer to approximately one minut, for example. Within the stopping time 31 the pressure balance between a discharge pipe 38 and a suction pipe 39 of the compressor is maintained. After the termination of the stopping time, the compressor 1 enters a re-operation, and the defrosting operation 32 is started. When the defrosting operation 32 is terminated, the compressor 1 is continuously operated as it is and the four-way valve 2 is again excited and reversed. Then, the compressor 1 causes a compression coolant to flow to the side of an indoor heat exchanger 5 and at the same time, drives a blower 13 of the heat exchanger 5 to return back to the space heating operation.
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