In my coach I have two roof top AC's (not heat-pumps), and a single LPG furnace. They are controlled (and I say that with a sarcastic smile) by a 4 button Comfort Control thermostat.
I've tried several suggestions I've read on these forums, to reset the system hoping to get more accurate control on the temperature in the coach. Nothing to date has worked. The temperature you enter for the zones seems to have no bearing on the actual temperature the units start and stop at. Seriously, depending on the time of day, the position of the sun, etc.. there could be anywhere from 3-6 degree difference between the thermostat reading, and the actual temperature in that space.
I have two independent digital thermometers that I keep in those two zones. They are far more accurate than the temperature sensors for the HVAC system. And, I actually have a third one I move from zone to zone to double check my other two digital thermometers.
So, here's my real question. Has anyone hacked the system, and used another manufacturer's digital thermostat to control the HVAC system? In my former brick and mortar home I had a digital thermostat that was amazing at keeping the house temperature accurate. In the coach, the connection from the thermostat to both ACs and the furnace is just a 4 wire RJ-11 modular plug, so it doesn't seem impossible to do using a telephone box as an intermediary. I'd be willing to give it a shot, but would love to hear from anyone else who made the attempt, especially if it was successful.
Positive suggestions are encouraged, and please be kind. Not all of us are as knowledgeable, or as smart as some of you think you are