Reefer Calibration?

The intake air temp can be calibrated and set by a technician. They'll place a pre-calibrateed wireless transmit thermometer on the floor in the nose and close it up and ideally will set a near freezing temp and verify/set, then run the temp up 20-30 degrees and insure it properly tracks there as well. They rarely get off enough to create problems, though. However if a thermostat is truly bad (defective) it can be off enough to cause serious problems

 

Reefer computer uses calibrated thermocouples to measure temperature. If sensor is out calibration computer will set the alarm code.
For good sleeping I use 3 sensors ACURITE thermometer. 1 sensor front, 1 on the middle 1 on the tail. Place them high enough as lumpers couldn't hit with high stack pallets.
Multi-Sensor Thermometer with 3 Temperature Sensors

 

The discharge and return air sensors on TK are graded but that shouldn't be a problem unless one of them has been changed or the micro has been changed and the mechanic didn't set(calibrate) the numbers,which can happen.

 

You can put sensors in front and middle trailer to control temperature. I was surprised by difference between front and rear. Front is much hotter.

 

Actually there is. It's called a temperature uniformity survey or TUS. I do them several times a year.