Can I Use the DMC79FR Thermostat to Upgrade My Duo-Therm Quick Cool AC to Digital?
Updated 05/15/2026 | Published 05/11/2026
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Question:
I have a duo therm quick cool dometic ac unit. What controller kit do I need to convert to digital thermostat? The unit is not a heat pump nor does it have a heat strip. The rv has a separate furnace that works off the same analog thermostat.
asked by: Larry
Expert Reply:
Hello Larry,
I get why you were looking at the # DMC79FR, but that one isn’t going to do the job for your setup. It’s just a thermostat replacement for systems that already have a digital control board. Since your Duo-Therm Quick Cool is still running the older analog style controls, there’s nothing there for that thermostat to talk to, so it wouldn’t actually run your A/C or furnace.
What you’ll need instead is the full conversion kit, part # DMC83ZR. That gives you both the digital thermostat and the new control board that installs up in the ceiling assembly. That control board is really the key, because it replaces the old analog setup and lets the new thermostat control both your A/C and your propane furnace from one spot, just like you’re used to now.
The install is pretty straightforward if you’re comfortable with basic wiring. You’ll pull down the inside A/C cover to get to the control box, remove the old analog board, and swap in the new one. As you’re doing that, you’ll move your existing wires over to the new board, including tying your furnace wires into the correct terminals so everything still runs through the same thermostat. Then you’ll run the included harness to your wall, mount the new thermostat, and plug it in. Once you power it back up, it should recognize the system and be ready to go.
Where people usually run into trouble is either leaving part of the old analog board in place or getting the furnace wires on the wrong terminals, so it’s worth taking a second to double-check those as you go.
Once it’s in, it’s a nice upgrade and a lot easier to live with than the old analog controls.
What kind of trips are you getting ready for once you’ve got the A/C dialed in?
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Replacement Single Zone Thermostat for Dometic RV Air Conditioners - Black
- Accessories and Parts
- RV Air Conditioners
- Thermostat
- Black
- Dometic
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Bill R.
5/13/2026
With regards to instructions listed above for full conversion kit, part # DMC83ZR, I'm wondering how people normally get the new wiring harness from the control box over to the wall T-Stat location. Is there a conduit in there? Surely not surface mount?!