How to Troubleshoot and Reset Dometic Duo Therm Thermostat?

Last Updated on September 19, 2023 by

Dometic Duo Therm Thermostat can be a bit tricky for a person to understand in order to fix things when it doesn’t seem right. You could experience issues if you broke Dometic Duo Therm Thermostat by any incidence or by any hard luck. It requires expertise and proper experience to understand what things are to be checked before you mess around anything on it.

Not all things will work right. That is only the manner in which it is, and to sort those RV problems out appropriately, you need to check out the straightforward steps first. Then, at that point, continue on to the more costly and muddled sources in case you can’t find a solution with simple steps.

Discovering the issue will take some time and might be in the most unrealistic of spots. There is a system reset choice that might tackle your concern, yet once in a while, the least complex things are the source. To investigate this issue, look to your circuits, including the ones under the fusebox of your RV.

You need to be sure you know what you are doing and see which wire or what else is causing the problem. To dive deeper into fixing a broken or problematic Dometic Duo Therm Thermostat, you can read our article in detail to find out how you can fix things all by yourself. But before we move to the solution, we need to see the problems with Duo Therm Thermostat.

Dometic Duo Therm Thermostat

Dometic Duo-Therm Thermostat Problems

People do wish for everything to go just fine, but that doesn’t really happen. Things can get messy, especially when there is an electrical fault. The Duo Therm Thermostat problems can be a headache, and some of them are.

  • Sometimes the thermostat doesn’t turn on, or it won’t stay on, and it can mostly relate to a switch problem. This would cause it to lose power. It may be due to a crack in the solder or something that may be dropping the power, which is why the switch isn’t receiving any power at all.
  • In such a situation, you need to replace the solder in case if you cant actually help to fix the problem. Replacing the solder will allow you to provide a better and stable socket for power.
  • Another problem with this type of issue is the Cracked Trace, in which you can look for the problem by using your finger and moving it over the circuit board in order to check for any cracks. Anything like a small piece of wire or a crack in the board would be an issue, and you can fix the problem by holding it tight altogether.
  • There is another problem of buttons not working sometimes that mostly occurs when there is too much dust collected inside the thermostat, and it breaks the connection for power. In order to fix this problem, you need to remove the cover and start dusting off the board and circuit from the dust and clean it properly for every switch. Clean every inch and every corner of the buttons so that they can start working properly like before.
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After following this procedure, you can expect it to work properly. In case your AC is not cooling at the right temperature, or you see a variance in the temperature balance, then you need to take a reading. For this, a handheld thermometer will be used at different points of the room or cab where the AC comes on. Turn on the device and record the reading with AC, and then turn off the AC and record the same reading for temperature.

It will show you the positive or negative side of the temperature, and in case that the gap between it is larger than expected, then you can perform a reset on the thermostat so that it performs correctly afterward. In case you can’t fix it, you should contact a professional or a technician with the help of the owner’s manual to fix things up.

Troubleshooting Dometic 5 Button Thermostat

There is a simple procedure that needs to be followed to troubleshoot the Dometic 5 button thermostat.

  • Switch off your RV and make sure no electrical connections are on.
  • Then you can press the zone button as well as the mode button at the same time while you switch the power back on altogether.
  • The digital display of your RV should pop up the FF letters as long as you keep the buttons pressed. It will be gone when you release the buttons. This process may normally take 15 seconds to make the font appear on the screen.
  • This will allow your electrical system to reset once and for all, and you can then check if the problem is fixed for you or not.

Remember that the reset system only works if you have an active and working system for the electronics. In case you have bad wiring, blown a fuse, or loose cables, this may not complete the procedure. Make sure that everything is just in the right place so that you can fix the thermostat’s operation.

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In case you fail to fix the problem, the experts and technicians can be of your help if you contact a Dometic company who will provide the professionals to do your work.

Duo-Therm Comfort Control Reset

The comfort control for Duo Therm can also be reset by a simple procedure. It can help you to recollect previous program memory from factory settings and remove the unusual data from memory to work with a fresh start. The temperature will be about 72 degrees F for cool, and for a warm temperature, it may be about 68 degrees F.

The means are somewhat more involved than in the past segment.

  • Turn the gadget on, and the light and annunciator information will be shown. In case they are, continue on to stage 2, and in case they aren’t, then read your manual segment 5.1.
  • Press the mode button to initiate the annunciator light.
  • Then, simultaneously, press the right and left buttons and hold.
  • Now, while these buttons are squeezed, utilize one more finger to press the mode button and make it work immediately. You just need to squeeze that button once as of now.
  • When you release the mode button, you can also leave the right as well as the left button.
  • Press the mode button once more. The light should turn off, and the mode should say ‘off.’ In case it doesn’t, repeat the step once again.
  • Test the framework to ensure the system is reset and is working.
  • When you see it is working, re-program your settings to the levels you need.
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In case that you don’t have a manual for this comfort control framework, you need to get a downloadable manual for it, or you can go to the closest Dometic vendor to see where you can get a printed copy.

Understanding If RV Thermostat is Bad

RV thermostats can normally last for about 10 to 15 years easily. During this time period, it is possible to witness a lot of technical problems with these thermostats if the RV is abused or used roughly in the past years. This kind of issue is usually found in a pre-owned RV.

The reasons that any thermostat may turn bad can be due to awful wiring, dust, soil, old wiring, and outright mileage. Here are a few different ways to tell if your thermostat isn’t filling in as it has to:

  • It is possible that the thermostat won’t respond to your commands when you use the buttons or controls.
  • Sometimes it has no power due to free or loose wires. The connection of the wires can somehow break or be detached due to bumps or any other reason over a long period of time.
  • Wires could come free, a breaker breaks, or it very well might be detached.
  • The battery runs out of power, or sometimes the screen doesn’t turn on, or it is faint.
  • The AC or adapter may not turn on, and you can adjust temperatures for it by yourself in case it shows the levels on the machine. Sometimes it shows the level, but you cant adjust it.
  • The radiator will not wind down when a certain temperature setting has reached its peak point by working.
  • The setting on the indoor regulator doesn’t coordinate with the temperature in the room.

You might discover these issues occurring after you purchased a restored indoor thermostat. You might have thought you were setting aside cash; however, a restored unit generally comes without guarantees or certifications, is seriously wired or fixed with second-hand parts, and so on.

You should be purchasing new parts and try to watch DIY for each problem to easily get a fix for your trouble. It is ideal to have an understanding of the electronics in your RV.

Testing Duo-Therm Thermostat

You need to perform a proper test to check for the problems in your thermostat. Old or used duo therm thermostat can be faulty sometimes, which is why you need to be sure about its working. You can start with the switch to on position. Then, you should verify whether the DC volts are right, and they ought to be somewhere in the range of 10 and 30, just as actually take a look at the extremity.

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Then, at that point, do a reset for the whole system, and if nothing turns on or there is an issue with the screen, then you realize that there is a major issue with the wiring or your thermostat. If the right setting doesn’t show up on the screen, check again for the cables and management to ensure it is fixed. If not, regardless, you might need to change the whole gadget.

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Replacing Duo-Therm Thermostat

In case you have a Duo-Therm thermostat, and you are about to replace it manually all by yourself, then you have to be sure that the latter is running on the batteries. Make sure that the new unit that you are adding has the same terminals as the RC, G, H, W, RH models of the Duo-therm thermostat.

  • You can start by disconnecting the wires from the electrical system first so that the connection is removed, and you can hook those cables with the new terminals.
  • Don’t forget to label the wires that you just connected before putting them into the hole back again so that it will make your replacement procedure easier.
  • Now, you need to test the new thermostat by turning on the lights and appliances that are powered through it before you put it on the wall.
  • It is recommended that you take expert help for the connection of wires and then put the cover back on the socket.
  • Some models may need 24 volt AC power to get them operational.

You can also get more information and help from their support page with a lot of links and support FAQs related to the problem.


This was a discussion about troubleshooting and resetting the Dometic duo therm thermostat in an RV with easy steps. We discussed its easy fixes for replacement as well as for improving it.


How to fix and reset Dometic Duo Therm Thermostat?

There is a procedure through which the Dometic duo therm thermostat can be fixed in some cases.

Here are the steps to perform.

  • Turn on the thermostat and then touch any button on it to turn the Back Lights ON.
  • Now hold down both of the UP and DOWN Buttons.
  • Press and then let go of the MODE button.
  • The let go of the UP and DOWN Buttons.
  • Then, you have to again press and let go of the MODE button.
  • The Back Lights will automatically switch off to signal success.

Can the duo therm thermostat be fixed?

Duo therm thermostat can be fixed, but it’s always a better choice to replace the thermostat with a new thermostat instead of fixing it.

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About Ted Mosby

I am Ted Mosby from Cleveland, Ohio. I am a Freelance Architect. I live in New Jersey, USA right now and I take my RV every alternate weekend. I own a Forest River Berkshire XLT Diesel 45A Class A Motorhome. As I am a Freelancer I can work anywhere so most of my work is done inside my camper remotely.