The normal operating temperature in the freezer compartment is 0 degrees. The fresh food compartment normally operates at 37 degrees. Fluctuations above and below these normal operating temperatures can be caused by the automatic defrost cycle, cycling of the compressor and opening of the fresh food and freezer compartment doors. Ambient temperature and the amount of location of food items loaded in each compartment can also affect the temperature fluctuations. A freezer thermostat controls the cycling of the compressor in conjunction with an Adaptive Defrost Control board. Refrigerator temperature is controlled by a fresh food compartment thermostat that is used to open and close an air damper in the top left wall of the refrigerator. The normal method of measuring refrigerator temperature is to place an accurate thermometer in a glass of water on a middle shelf of the fresh food compartment. In the freezer compartment, a thermometer is normally placed between packages of frozen vegetables to accurate measure freezer temperature. These methods eliminate fluctuations normally caused by factors mentioned above. In an empty refrigerator and freezer with no door openings at mid-point control settings, this unit is designed to maintain -1 to 4 degrees in the freezer and 34 to 39 degrees in the refrigerator. Exact variances in temperature beyond these controlled conditions are difficult to predict. I recommend measuring your normal operating temperatures in the refrigerator and freezer by the normal methods noted above.
This refrigerator has an Adaptive Defrost Control board that initiates defrost cycles as needed between 6 and 72 hours apart based on compressor run times and other factors. Each defrost cycle can last up to 30 minutes. During the defrost cycle, the compressor and evaporator fans are turned off. A heater under the evaporator turns of and melts the ice and frost off of the evaporator. If the temperature of the evaporator rises to 47 degrees, a defrost termination thermostat will open to turn off the heater. If the temperature does not reach 47 degrees, then the cycle will time out after about 24 minutes. A six minute delay will occur after the defrost heater shut off to allow time for condensate to drain from the evaporator. The compressor and evaporator fan will then restart to resume normal cooling. Understanding this cycle and the other factors affecting temperature variance in the refrigerator and freezer may help explain the fluctuations that you are seeing. Depending on your method of measuring the temperatures that you are reporting, these readings may or may not be normal. I recommend monitoring the refrigerator temperature using the glass of water as described and measuring the freezer temperature by placing the thermometer between packages of frozen food. If the operating temperatures are normal, then the unit should be operating properly. If not you could have any number of different problems or component failures that could prevent the unit from cooling properly.
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