Carrier 2100A defrosts too often

What was the outside temperature at the time? And what temp are you trying to cool it down to?

 

I have a thermo king. It’s programmed to defrost every six hours. I would guess carrier has a similar function.

 

This is normal for summer time. Reefer unit has sensor for air flow. If flow restricted it starts defrosting cycle.
Shipper want us pre cool then cold trailer got wet from air humid. Some products evaporate water such as fresh produce or potato.
Unless you have trailer with holes or saturated with water. Did you check trailer roof? No cracks or holes? How is door seal looks like?

 

Enter advanced user mode on keypad and change the defrost default Time range.... At least check it someone might have set it very frequent.

I usually run mine 3 hours on produce and 6 or 12 hours on normal Freight.

.... The other likely culprit could be you need to have the evaporator washed out... it could be clogged causing the pressure delta sensor to trigger defrost.


Side note, your evaporator should be backwashed every 6 months or less for peak performance.