| 摘要 |
PURPOSE:To provide a simple construction of defrost control device by a method wherein a heating operation is carried out after a starting of the heating operation until a desired time is elapsed, and after the desired time is elapsed, the defrost operation is controlled by either a sensed temperature of a temperature sensing means or a sensed electrical current of an electrical current sensing means. CONSTITUTION:When a heating operation is started and a timer count of a desired period of time T is set by a microcomputer 11, a heating operation is continued until the time T is elapsed. As the time T is elapsed, an inputting of a piping temperature (t) is carried out by a piping temperature sensing element 6 and then a comparator 14 may judge if the piping temperature (t) is lower than a set piping temperature (t1). If the piping temperature (t) is higher than the set temperature (t1), the comparator 18 may judge if an electrical current I is lower than a set electrical current I1. If the condition of t<=t1 or I<=I1 is fulfilled, each of the transistors TR1, TR2, TR3, TR4 is operated, a four-way changing-over valve 2 is changed over and then a frost removing operation is performed in a refrigerating cycle. With this arrangement, it is possible to perform a positive frost removing operation only with a temperature sensing or an electrical current sensing.
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