Testing and Adjusting a Refrigerator Thermostat

Lead Image
  • 1-3 hours
  • Intermediate
  • 0-300
What You'll Need
Ohmmeter

The refrigerator thermostat, which is generally located inside the appliance, is the controlling device that allows users to adjust the temperature inside the fridge. This device controls the cooling system, which includes the condenser, the compressor, the evaporator, and the metering device. Once the thermostat is adjusted to the desired temperature, it will act as a switch to activate the compressor in order to cool down the temperature and shutting it down after that temperature is reached. It will then keep going ON and OFF as the fridge's temperature fluctuates up and down in order to maintain at an acceptable preset temperature range.

Testing the Refrigerator Thermostat

The efficiency of the thermostat is very important in the maintenance of proper temperature inside the fridge. If the thermostat is faulty, it causes unreliable temperatures inside the fridge that may compromise the freshness of its contents. To check if the thermostat is working fine, a simple test is required.

An ohmmeter will be required for the following test and set to the lowest scale. The thermostat dial then needs to be turned fully counterclockwise or at the zero setting. The thermostat is located just at the back of the dial. Remove the plastic cover to expose the thermostat. Locate the two terminals on the thermostat and touch one probe of the ohmmeter to each terminal. The meter shouldn't get any reading with the dial at this position.

Gradually rotate the dial clockwise until it reaches a temperature level colder than the ambient air around it. The meter should then read zero or 0.2Ω if the thermostat is working properly. However, if there is a resistance higher than that value, then the thermostat needs to be replaced with a new one before it spoils the food inside the fridge. Remember that an unstable thermostat will result in unreliable temperatures inside the fridge.

Adjusting the Refrigerator Thermostat

Since the temperature inside the fridge is very critical to food, the thermostat should be set at the correct or ideal temperature. A very low temperature can cause the food to freeze and burn, while a high temperature can cause the food to spoil. Therefore, the thermostat should be set at the right temperature, always. It is also a good idea to check the temperature inside the fridge to check if the thermostat is adjusted to the optimum temperature. This can be done by using a meat thermometer.

The ideal cooling temperature for food inside the fridge is 37-degrees F or within a range between 30 to 40-degrees F. Set the dial to that temperature or set it in mid-range if the dial is not in numerical values. Next, use a thermometer to verify if the temperature is between 30 to 40-degrees. Adjust the dial accordingly to get the desired temperature.

Sometimes, the thermostat setting might noticeably differ from the fridge's temperature, especially when the temperature is too low. In order to correct this, allow the fridge to go into defrost mode. This can be done automatically by rotating the dial fully counterclockwise to zero, or by unplugging it. Afterward, reconnect the fridge and wait for the temperature to cool again. Set the dial to 37-degrees again or at mid-range and recheck the temperature. Adjust the thermostat if necessary.

Testing and adjusting your refrigerator's thermostat should be a regular part of your maintenance routine, just like defrosting the freezer. This will save you from having spoiled food.