Can you please let me know what thermometer you are using to measure superheat in a walk-in freezer.
I have been using a multi-meter with a type K thermister adaptor measuring pipe surface temperature but at –20ºC the multi-meter (fluke) does not seem to give stable readings.
I have looked into other electronic thermometers but they are all rated at an ambient of <0ºC. Infrared thermometers have the same problem.
Any suggestions would be appreciated

Mark