defrosting operation the temperature in the refrigerator never rises to such a high degree that the stored food is melted or spoiled after executing the step 1 the microcomputer 23 returns the operation of the refrigerator from the defrosting operation to the normal cooling operation however since there were defects in the defrosting system the defrost heater 71 is not energized anymore for without executing the step k the integrating timer 25 of the microcomputer 23 is kept reset as another example in case the d u00ae frost heater 71 is damaged in spite of the defrost heater exciting signal 45 provided from the microcomputer 23 the defrost heater 71 does not generate radiant heat and the temperature of the evaporator 9 detected by the defrost sensor 37 does not reach the prescribed value within twenty minutes to one hour therefore the count of the warning timer 29 reaches the prescribed value such as three hours before the h level defrost completing signal 17 is provided to the input port of the microcomputer 23 thus also in this other example in step j the yes path is taken in step m the error message is displayed and in step 1 the defrosting operation is forcibly completed then the operation of the refrigerator is forcibly r u00ae turned to the normal cooling operation as can be understood from the above described embodiment any.