How to Recalibrate Your Thermometer

A bimetal Insta-Read® dial thermometer may lose accuracy after years of use or after a particularly hard jolt. The hex nut on the underside of the thermometer is used to bring the thermometer back into calibration. First, you need a container of water at a known temperature – the closer to the mid-range the better. A fever thermometer is ideal for measuring the temperature of the water.

Using an Ice Slurry

Ice water* (3/4 ice to 1/4 water) in a glass can be used to recalibrate your thermometer.

  1. Immerse the thermometer stem in the water to a depth of at least 2 inches.
  2. Hold the dial firmly (pliers or a wrench may have to be used) and slowly rotate the hex nut beneath the dial. Use the pliers or wrench to adjust the next nut. The pointer will start to move.
  3. Rotate the nut clockwise to increase the reading. Rotate the nut counter clockwise to decrease the reading.
  4. Stop adjusting when the pointer indicates the temperature of the water.

*NOTE: It is very difficult to get a 32°F/0°C ice water temperature. It will probably be closer to 34°F/1°C.

Using Boiling Water

Boiling water (adjust for altitude above 1,000 feet*) can be used to recalibrate your thermometer. Please be cautious around boiling water.

  1. Immerse the thermometer stem in the water to a depth of at least 2 inches.
  2. Hold the dial firmly (pliers or a wrench may have to be used) and slowly rotate the hex nut beneath the dial. Use the pliers or wrench to adjust the next nut. The pointer will start to move.
  3. Rotate the nut clockwise to increase the reading. Rotate the nut counter clockwise to decrease the reading.
  4. Stop adjusting when the pointer indicates 212°F/100°C.

*NOTE: For every 500 feet of elevation, reduce the expected boiling point of water by 0.5°F/0.25°C.

Using the Recalibration Tool on Sheath

ProAccurate® models IRT220, IRT550, IRXL220, IRXL400, IRT220-F, IRB220-F, IRB220-F-6.5 and IRTL220-F

  1. Seat the hex nut on the thermometer into the head of the sheath.
  2. Immerse thermometer in sheath into at least 2 inches of ice water* (2/3 ice to 1/3 water) or boiling water (212°F/100°C at sea level).
  3. Adjust hex nut beneath dial as in steps 3 and 4 above.

Recalibrating Digital Thermometers

Models DTW450L, DTW450, Q2-450X, DTQ450X, DTT450

  1. Place the stem into a glass of ice water (3/4 ice to 1/4 water).
  2. Press the CAL button for 2 seconds. The display will be blank for 2 seconds. Release the CAL button and 32.0°F appears.

NOTE: To avoid accidental recalibration, this function only works when the water temperature is 30 to 34°F. ERR will appear for 2 seconds if the water is not within this range and then return

2018-07-14T20:37:23+00:00