| 摘要 |
PROBLEM TO BE SOLVED: To provide a defrosting controller capable of switching a four-way valve surely. SOLUTION: The defrosting controller detects an indoor pipeline temperature, capable of detecting the condensing temperature of refrigerant, by an indoor pipeline temperature detecting means 8, stops a compressor for a predetermined stopping distance by a compressor operation stopping means 15 when a defrosting operation starting signal is inputted from a defrosting operation switching means 13, and during this stopping distance, the controller decides whether the indoor pipeline temperature, immediately before the inputting of the defrosting operation starting signal, is higher than a predetermined temperature stored in a temperature memory means 9 or not by a temperature deciding means 10, and a valve opening pulse number, having a large value, is set by a valve opening pulse deciding means 12 when the temperature is higher than the predetermined temperature while a small valve opening pulse number is set when the temperature is lower than the predetermined value whereby a motor- driven expansion valve 6 is opened by an expansion valve driving means 17 through a valve opening pulse outputting means 16. According to this method, a differential pressure between a high pressure and a low pressure in a refrigerating cycle is secured so as to be neither too much nor too little just enough whereby the four-way valve can be switched surely.
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