Combine compartments?

Old thread... But its worth a reply as its a fairly common.
Glad it worked out for you.
You did the right thing pulling the cold wall down.
Was it in continuous run or start stop? As defrost requires compressor running.
If center load is wet or not frozen completely the evaporator will freeze up and need frequent defrosts. Multi temp evaporators are small and don't have have much real-estate, lending themselves to icing up. Sometimes its good idea to manual defrost before/while loading to give you an edge.
TK or Carrier? Not all multi temp reefers can heat, defrost, and cool at same time. It depends on the options chosen when purchasing unit. Its possible that center unit has to wait for front evaporator to enter defrost mode. Contact manufacturer with model and serial numbers to find out exactly its capabilities.
I preferred old style TK 3 zone controls with off/on toggle switch for each zone. The logic of zone controls seemed clear.
The 8 new button control panel starts to get confusing with 3 or more zones when your having problems.

 

Welcome to multi temp reefer madness!
2nd and 3rd evaporator temperature sensors tell temperature at evaporator, NOT necessarily the loads circulating air temperature.
Get couple temperature probes to verify compartment temperatures.
If running start stop mode make sure the temperature start and stop are OK for each zone
Your going to have to baby sit reefer until figuring out its idiosyncrasies. Downloading reefer data and reviewing it will give you a good idea of temperature holding characteristics.
Multi temps have many things affecting compartment temperatures. Most important is cold wall, don't skimp on quality wall and keep sealing areas it in good repair. Even small leak between front compartment will make 2nd compartment too cold, 2nd evaporator temperature reading may NOT reflect temperature at floor. Things will change depending on outside temperatures.
Also air circulation is poor with ceiling evaporators compared to front unit. When loading take air circulation into account!.
In winter be careful with loads requiring heat as ceiling evaporators fans don't blow hard and temp sensors at ceiling not at the trailer floor.
Keep ceiling evaporator drip trays drains clean and hoses angled down.
Get a produce temperature chart and know what products cant be shipped together like apples and bananas etc...

 

Unless it’s ice cream, I would of just set it to 15* and let it all ride