| 摘要 |
PURPOSE:To eliminate the wrong defrosting operation by a method wherein defrosting is performed only in the case that the running current of an air conditioner is below the predetermined value for a certain period of time, which is gone back to the past since the time point that the difference between the temperature of an outdoor heat exchanger and the temperature of the air after passing through the heat exchanger exceeds the certain value. CONSTITUTION:A sensor 9 to detect the temperatue of an outdoor heat exchanger 4 and a sensor 10 to detect the temperature of the outdoor air after passing through the outdoor heat exchanger 4 are provided. Further, a means to defrost the outdoor heat exchanger 4 when it has frosted and a means to control the operation of the defrosting means are equipped. In addition, the running current of an air conditioner is time-functionally memorized by a control circuit 12. Furthermore, a means to judge defrosting conditions in response to the outputs of sensors 9 and 10 and of a current detecting means and a means to output defrosting signals to the defrosting means in response to the output from the judging means are also equipped. As a result, defrosting is started under the conditions that the temperature of the piping of the outdoor heat exchanger 4 is below the predetermined value and at the same time the difference between the temperature of the piping of the outdoor heat exchanger and the temperature of the air after passing through the outdoor heat exchanger exceeds the predetermined value and, in addition, the running current of the air conditioner is below the predetermined value for a certain period of time, which is gone back to the past since the time point that said difference exceeds said predetermined value. |
