The thermostat of a refrigerator works on the same principle as that of a house in that it controls temperatures. Some refrigerators have separate controls for the freezer and refrigerator compartments and others have one control for both units. When the thermostat on your refrigerator is not working properly, it causes food to spoil, which can lead to health dangers.
Not Cool Enough
If your refrigerator does not seem to be keeping your foods cool enough or at the appropriate temperatures, there may be something wrong with the thermostat. To test this, turn it up a degree to check if the compressor turns on. If the compressor doesn't engage, it is possible that the problem may be more extensive than just the thermostat. If the compressor does engage, check the temperature again after 24 hours to see how much it increased. You can do this by using a simple appliance thermometer. If the temperature has not changed, you likely need to replace the refrigerator thermostat.
If food freezes in your refrigerator compartment areas, most likely the thermostat is not functioning properly. Generally, it is easier to replace the thermostat rather than trying to fix it. Test it by again using an appliance thermometer. Turn the thermostat up two degrees, wait 24 hours and check items for freezing. If it is still apparent that the refrigerator has regions that are too cold, replace the thermostat.
Ideal refrigerator temperatures should be between freezing at 32 degrees F and 40 degrees F. This is the recommended temperature range as determined by the University of Nebraska-Lincoln to maintain food quality and slow bacterial growth. It keeps temperatures just above freezing to prevent this happening to items such as lettuce or other tender vegetables.
Types of Thermometers
The easiest way to check for symptoms of a thermostat not operating properly is the use of an individual thermometer. Do not rely on the thermostat to give an accurate reading as this will not be correct if not working properly. The best way to check is to use either a liquid-filled or a bimetallic-coil thermometer. Place it in the refrigerator section of the unit and monitor temperatures over a period of a few days as you adjust the thermostat up or down. If there are no fluctuations as you experiment with settings, it is a good indication that the thermostat is bad.