Recommendation for Checking Bimetal Thermometer Accuracy

Using a dry block reference device and three temperature points

• Dry block calibrator must be certified and NIST traceable. The accuracy of the equipment must be at least four times more accurate than the accuracy of the product being calibrated
• Do not reset or adjust the calibration until after all check point readings are recorded. Adjusting the set point at a different point than the original set point can cause the thermometer to become out of tolerance at the other end of the range.
• For each test point complete these steps:
• Insert the stem of the thermometer into the calibration reference device so that the groove on the stem is completely immersed into the temperature zone
• Let the thermometer rest until the pointer is stable, a minimum of 2-3 minutes
• Lightly tap the case to stabilize the instrument
• Record the reading

After checking all the check points:
If any of the temperature readings are outside the accuracy tolerance the set point will need to be adjusted. Please contact Tel-Tru for help if you are unsure of the correct adjustment; we will need to know your temperature check points and thermometer readings. Tel-Tru thermometers are set at the mid scale of the range so they will be within tolerance at the low and high ends of the range.
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