Abstract: A method of refrigerator control for operating a refrigerator which may experience an abnormal temperature condition due to operation in low ambient temperatures includes a temperature sensor for sensing the temperature of a portion of a refrigerator compartment in order to detect an abnormally low temperature in another portion of the compartment. If the compartment temperature at the end of a predetermined length of time since cooling was last supplied to the compartment is below a predetermined value, then an abnormal condition is assumed to exist and corrective action is taken to eliminate the abnormal condition. A preferred form of corrective action is to prevent compressor re-energization until the compartment temperature reaches a second predetermined value.

Abstract: A refrigerator control for operating a refrigerator which may experience an abnormal temperature condition due to operation in low ambient temperatures includes a temperature sensor for sensing the temperature of a portion of a refrigerator compartment in order to detect an abnormally low temperature in another portion of the compartment. If the compartment temperature at the end of a predetermined length of time since cooling was last supplied to the compartment is below a predetermined value, then an abnormal condition is assumed to exist and corrective action is taken to eliminate the abnormal condition. A preferred form of corrective action is to prevent compressor re-energization until the compartment temperature reaches a second predetermined value.

Abstract: A door ajar alarm system for a refrigerator-freezer, the system having a variable alarm delay period. The door ajar alarm system includes a control which may be digital or analog for monitoring various operating conditions of the refrigerator such as the temperatures of the refrigerator compartments and whether the refrigerator is undergoing a defrost operation. The control determines the alarm delay period in accordance with the monitored conditions such that the delay period is decreased in response to each monitored condition which reaches a predetermined status. The door ajar alarm thus alerts the user to operating conditions which are likely to produce an undesirable temperature within the refrigerator more rapidly than usual or to produce temperatures from which recovery is unusually slow.

Abstract: An adaptive demand defrost control system controls the length of an interval between defrost operations in accordance with the number and duration of compartment door-openings, the duration of a previous defrost operation as corrected by the temperature of the evaporator prior to defrost, and the length of time the compressor has been energized. A count is stored which is varied according to a decrementing schedule, with the decrementing schedule in turn being based upon a comparison of the corrected defrost duration with either a desired defrost duration or a range of desired defrost durations. A defrost operation is initiated when the count reaches a predetermined value. An alternative embodiment of the invention develops an indication of the ambient humidity and controls humidity-dependent apparatus in accordance with the indication.

Abstract: An adaptive demand defrost control system controls the length of an interval between defrost operations in accordance with the number and duration of compartment door-openings, the duration of a previous defrost operation as corrected by the temperature of the evaporator prior to defrost, and the length of time the compressor has been energized. A count is stored which is varied according to a decrementing schedule, with the decrementing schedule in turn being based upon a comparison of the corrected defrost duration with either a desired defrost duration or a range of desired defrost durations. A defrost operation is initiated when the count reaches a predetermined value. An alternative embodiment of the invention develops an indication of the ambient humidity and controls humidity-dependent apparatus in accordance with the indication.