Not sure how much you are going to gain but can you tell me how many zones you have on the thermostat and which zone is the problem?
Yes I just checked. On some of the thermostats it is an option to add a remote thermostat to the control box in the AC unit but on your model that is not an option. The only thing you can do is re-locate the thermostat or at least experiment to see if you can get the temp dialed in. Being a tech I will say these are very touchy and the thermostat needs to be away from any windows, drafts, heat etc and needs to been in the line of circulation to sense the correct temp. I would pull the cover off and remove the screws and let the thermostat hang down and see what happens, you should have enough of wiring to do this.
I worked for one manufacturer and they put the thermostat right on the audio video cabinet, well that cabinet got really warm and would give a false reading to the thermostat.
There are no settings on this and the only other thing to try, is if this has a glass fuse under the cover, pull it wait a few mins and put it back in, sometimes this will reset the thermostat and also takes care of some faults when they occur.
I would try and move the thermostat around and see what happens, it will not take much..
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