I thought I should check my Thermapen today. Being that I am new to using one I thought I'd look up instructions to do just that. Here is what I found, just thought I would share what I found.
Calibration should be performed at room temperature, i.e. 70 F. Two known reference temperatures are required to calibrate the Thermapen. As a guide, ice water = 32 F (0 C) and boiling water = 212F (100 C). Ice water should be prepared by filling an insulated container with pea sized ice chunks and adding just enough water to cover the ice. Consideration should be given to altitude above sea level when using boiling water for a reference (Boiling point drops 1 degree for every 500ft increase in altitude).
1. Orient the Thermapen so that the display is facing down, with the probe facing to the right.
(Refer to diagram below)
2. Carefully remove the ThermoWorks label covering the calibration access holes and locate the two calibration adjustment screws.
3. Unfold the probe to turn Thermapen on.
4. Place tip of probe into ice water making sure that there is no contact between the tip of the probe and the container holding the water. Slowly stir the probe in ice water.
5. After waiting for the display to stabilize, use one hand to rotate the Thermapen until the display can be viewed. Use the other hand to insert a small slotted screwdriver into head of the “Zero” adjustment screw. Rotate the “Zero” screw until the display reads 32 F. Remove probe from ice water.
6. Place tip of probe into boiling water making sure that there is no contact between the tip of the probe and the container holding the water.
7. After waiting for the display to stabilize, use one hand to rotate the Thermapen until the display can be viewed. Use the other hand to insert a small slotted screwdriver into the head of the “Span” screw. Rotate the “Span” screw until the display reads 212 F. Remove probe from boiling water.
8. Place tip of probe back into ice water and check reading at 32 F (0 C). If reading is incorrect at 32 F (0 C), repeat steps 4-7 until the display correctly reads 32 F (0 C) and 212 F (100 C). Replace the ThermoWorks label over the calibration access holes.