3 Wire Thermostat Upgrade?

[Ovation12s]

I have a new Jayco 2022 264BH. It has a Dometic Capacitive Touch Thermostat, a Dometic DF series Furnace and a Dometic AC unit, with a model I've been unable to identify, since the manual doesn't list my thermostat. Probably have to climb up on the roof if we need that. I want to upgrade the thermostat because it won't maintain a temperature even in the vicinity of the thermostat. I'll probably have to do something with ducts as well, but I think fixing this is probably the first step. Problem is that the thermostat has only 3 wires: Red (+12 volts), White (ground), and the middle Green wire which says R10 and also C4 next to it on the circuit board (Could this be heat Relay/Compressor?). Most systems I've looked at have at least 4 wires, maybe 5 or 6, and some older heat only with 2. Is it even possible to upgrade this without replacing something on the furnace and/or AC units? This is only a guess, but does the green wire actually run to both the furnace and the AC unit, and the thermostat has a relay that adjusts this somehow, and the fan auto/hi/lo uses the +12v and grd? Maybe I could put some kind of a 3 position switch into the replacement thermostat with the green wire coming in with 2 wires coming out, one for the AC compressor terminal and one for the Furnace relay on the new thermostat? How would it know which unit to trigger though. This seems very strange.

[kblast523]

Originally Posted by Ovation12s

I have a new Jayco 2022 264BH. It has a Dometic Capacitive Touch Thermostat, a Dometic DF series Furnace and a Dometic AC unit, with a model I've been unable to identify, since the manual doesn't list my thermostat. Probably have to climb up on the roof if we need that. I want to upgrade the thermostat because it won't maintain a temperature even in the vicinity of the thermostat. I'll probably have to do something with ducts as well, but I think fixing this is probably the first step. Problem is that the thermostat has only 3 wires: Red (+12 volts), White (ground), and the middle Green wire which says R10 and also C4 next to it on the circuit board (Could this be heat Relay/Compressor?). Most systems I've looked at have at least 4 wires, maybe 5 or 6, and some older heat only with 2. Is it even possible to upgrade this without replacing something on the furnace and/or AC units? This is only a guess, but does the green wire actually run to both the furnace and the AC unit, and the thermostat has a relay that adjusts this somehow, and the fan auto/hi/lo uses the +12v and grd? Maybe I could put some kind of a 3 position switch into the replacement thermostat with the green wire coming in with 2 wires coming out, one for the AC compressor terminal and one for the Furnace relay on the new thermostat? How would it know which unit to trigger though. This seems very strange.

Electronics...everything and I mean EVERYTHING goes thru the box in the air return on the A/C It is all "logic and not as simple as an analog on-off switch. The CT thermostat sends specific signals to the control boards and magically controls the hear or a/c.

[Ovation12s]

Since this green wire is s just a single copper line, it would seem like you're saying it sends on/off pulses of some kind, almost like morse code, because it can't really send data like a true network would. Is that a correct statement?

[colby]

It's not cheap, but I have heard really good things about this replacement - https://www.microair.net/products/ea...-rv-thermostat

[kblast523]

Originally Posted by Ovation12s

Since this green wire is s just a single copper line, it would seem like you're saying it sends on/off pulses of some kind, almost like morse code, because it can't really send data like a true network would. Is that a correct statement?

The touch controls send variable voltage signals to the controller. It is not as simple as an on/off switch. The signals received in the control box determine what happens next. All three control wires are single strand copper wire. I am not familiar with which one does what, BUT I can tell you if you change the type of thermostat you have to change the controller. When I installed an optional heat strip, I had to change the thermostat and controller to a compatible set to operate the heat strip. When the rooftop unit was changed under warranty the service center 'forgot' to transfer the heat strip and although I didn't need it in Phoenix, they gladly installed it on my return home. The same applies for heat pump units. In order for it to work, the proper proprietary thermostat must be installed. These things are digital, so don't try to jack the system.

[Ovation12s]

Thanks, that helps clarify. It also tells me that Colby's post might be a good way to go on this.

[Ovation12s]

You Rock Colby!!! The RV 351 is an exact match for what I have. And while $249 might seem expensive, when you consider the hassle of replacing furnace and AC modules, running new wires, or worse paying some dealer yokels to do it this seems like a bargain if it actually improves things.

[colby]

Originally Posted by Ovation12s

You Rock Colby!!! The RV 351 is an exact match for what I have. And while $249 might seem expensive, when you consider the hassle of replacing furnace and AC modules, running new wires, or worse paying some dealer yokels to do it this seems like a bargain if it actually improves things.

I can't agree more, the time and effort to figure out where the potential missing pieces are, etc., just isn't worth it. Mine is working from what I can feel (I have not had the touch issues and the systems come on when they are supposed to based on feel), but this is in the plans at some point in time.