How to Calibrate a Refrigerator Thermometer

Step 1 - Prepare

Determine whether to use the boiling point method or the freezing point method. The boiling point method can be used ideally in elevations that are 1000 feet or less above sea level. The freezing point method can be used regardless of the elevation. Better yet, try both methods for comparison.

Prepare the boiling water as well as the ice if there isn’t any ice available yet. While waiting for the water to boil or the water to freeze, check where the calibration nut on the thermometer is located. This nut will enable thermometer adjustments. However, digital thermometers do not have a nut, but a reset button instead. This button only needs to be pressed after following the steps below.

Step 2 - Use the Calibrations Methods

To use the boiling point method, simply place the thermometer probe or stem into the container with boiling water and wait for at least 30-seconds or until the indicator on the thermometer stops moving. The reading on the thermometer should be 100 degrees Celsius or 212 degrees Fahrenheit.

To use the freezing point method, fill the container with crushed ice until it is full. Add a little tap water to the container to fill in the gaps. Place the thermometer probe or stem into the container and wait until the indicator stops moving or wait for at least 30 seconds. The temperature should be at 0 degrees Celsius or 32 degrees Fahrenheit. If this reading is achieved, then the thermometer is properly calibrated. If not, then proceed to the next step.

Step 3 - Calibrate the Refrigerator Thermometer

To calibrate the thermometer, find the adjuster nut and simply turn it until it reaches the correct temperature. If using the boiling point method, the temperature should be 212 degrees Fahrenheit or 100 degrees Celsius. If you are using the freezing point method, the temperature should be at 32 degrees Fahrenheit or 0 degrees Celsius. If the thermometer is digital, simply push the reset button and that will automatically calibrate the device. In order to ensure proper calibration, try using both methods.