I have a new Johnson Control unit for a chest freezer fermentation chamber. The unit is not behaving properly. When set at 65 degrees, three different thermometers inside my chest freezer read 72 degrees. Ordinarily, I would just set my temperature 7 degrees colder than my desired temp to compensate, but the relationship between the actual temperature and the set temperature is not linear. As a result, I am unable to keep a satisfactory temperature setting. I think the probe may
be malfunctioning or defective.
Should I just try buying a new probe and wiring it up? Something else I can try?