Refrigerator And Freezer Thermostat Replacement Information
Some thermostats read temperature by sensing the air. Some thermostats are imbedded into the evaporator coil for sensing the temperature. In some Walk-in cooler applications a pressure control is installed in the refrigeration circuit telling your compressor when to cut in and cut out.
If you are getting temperature fluctuations you may want to try and calibrate with an accurate digital temperature probe.
The picture above represents a pig tail style thermostat. The end portion or (Pig Tail) is inserted into the fin portion of the evaporator to sense the temperature of the refrigerator or freezer.