If you have the Dometic 3 button thermostat, you are likely experiencing some problems. This thermostat looks simple since it just has 3 buttons. With just those 3 buttons, you can operate the Dometic ac and your furnace thermostat. However, its internal design and functions are complicated, leaving RVgoers with many problems and frustrations.
Many people report problems such as “turns off by itself” and “the buttons don’t work” to name a couple.
This post will review the all too common problems with the Dometic 3 button thermostat, including:
- Communication Error
- Easy Touch Button
- How To Reset Dometic Thermostat
- Incorrect Temperature Readings
- How to change Dometic thermostat from Celsius to Fahrenheit
- Dometic Thermostat Replacement
As we uncover these known problems, there are some Dometice RV thermostat basics to know.
Table of Contents
- Dometic RV Thermostat
- Dometic 3 Button Thermostat Problems
- Incorrect Temperature Readings
- How to change Dometic thermostat from Celsius to Fahrenheit
- Dometic Thermostat Replacement
- Final Thoughts
Dometic RV Thermostat
If you have been an RVgoer for a while, you have seen your fair share of Dometic Thermostats over the years. They have been around since the 60’s, and can make a very reliable thermostat. They even make other things, such as the Dometic RV refrigerator. I remember one of my first RVs, it was a Viking pop-up. That camper was 15 years old, had a Dometic thermostat, and didn’t give us one day of trouble.
Fast forward to today, and the 3 button thermostat is a computer to operate the simple functions of your air conditioner and RV furnace. Don’t get me wrong, I love modern technology, but it needs to work! I can see how the Dometic Corporation was just trying to make a modern thermostat.
As we dive into the problems, we must note how they were derived. Compared to a basic analog thermostat, the 3 button problems are mostly due to the high number of gadgets that are trying to be used in a digital thermostat.
Dometic 3 Button Thermostat Problems
Many of the problems with this thermostat are that there is an unnecessary complication in what should be a simple function to operate your RV air conditioner and furnace.
With Dometic RV thermostat troubleshooting, there are some basic features to understand. The Dometic dual zone thermostat can function with multiple systems into one thermostat. But as we continue to learn, cramming all those functions into an RV thermostat with 3 buttons has its issues.
Communication Error
Did you know that the Dometic 3 button thermostat is just one part of your thermostat system? It’s true! Your thermostat, the part you see and touch to change the temperature, is just a controller that sends a signal to another computer system or comfort control center (CCC).
Inside your 3 button thermostat, you will notice only 3 wires. When looking at a wiring diagram, this thermostat wiring is for power, ground, and the other is communication to the control center.
The control center tells your RV furnace and RV air conditioner to turn on and set the temperature. It will even tell your heat pump or heat strip to turn on and off.
Any communication error between your thermostat and the Dometic comfort control center will result in an error code and render your thermostat, RV furnace, air conditioning, heat pump and heat useless!
In the owner’s manual, there is a list of error codes. They vary from errors such as out-of-range indoor temperature sensors to locking out your heat pump operation.
The most common error is E1, a communication error between the thermostat and the CCC (module board). This is the go to error for any communication issue. Unfortunately, this error code results in the “system will shut down”. Not very comforting when you want some heat or air conditioning.
Solution
This solution can be tricky as there could be an issue with the module, the thermostat, or the comfort control center, which is very difficult for an RVgoer to diagnose and fix.
The first thing you can do is inspect the wire and make there is a good connection. When you take your thermostat face plate off, you will see that there are 3 wires. Make sure they are all securely set in their pins. If any are loose, resecure with a small flathead screwdriver. Those small screwdrivers with glasses are a great tool for this task.
If the wire connection was good and you still get this error code, follow the system reset procedure in the next section.
How To Reset Dometic Thermostat
Since the thermostat is complex and there is a limited amount one can do, Dometic suggests trying a system reset before sending it off to a technician.
Like a laptop computer, try resetting the system to see if it helps. Unfortunately, there is no easy way to reset these thermostats. Other thermostats allow pressing 2 buttons, and the thermostat will reset. The only option for these 3 button units is a “hard reset.” Here are the recommended steps for a hard reset:
- Step 1: Turn off the Thermostat.
- Step 2: Remove the face cover gently to get inside the thermostat.
- Step 3: At the 3 wires in the upper left-hand corner. Remove the farther one to the left. This is the ground wire and will cut power to the thermostat.
- Step 4: Wait a few minutes.
- Step 5: Reconnect the wire.
- Step 6: Put the face cover back on the thermostat housing
- Step 7: Turn back “ON”
Tip: use a small eyeglass screwdriver to loosen the screw. Carefully remove the wire, and don’t let it touch any other metal. Again, this is not ideal, but Dometic didn’t make this easy, which is another problem people have.
Easy Touch Doesn’t Work
Did you notice that the button are not buttons? That is because they are what Dometic calls their Captive Touch Interface. This screen works similarly to a smartphone, using skin contact to function. Sounds great, but this fancy feature seems to cause frustration among RV owners.
Although this technology works great on cell phones, the thermostat is far from the same advancements as a touch-screen smartphone. The owner’s manual says it will not work if you have wet fingers, bandages, or gloves. Same as a smartphone, but I’m not sure if I need this hassle when I want to turn up the heat in my RV.
The first issue people have reported is that the touch face is erratic. They press the button once, and the sensor raises or lowers the temps multiple times above what the user intended.
Another issue is that it does what it wants to do. There are reports of the screen randomly raising and lowering the temp without the user’s contact. Some have used the word “possessed” when describing this thermostat.
Solution
The first solution is a quick check to see if there is water on the panel. As mentioned above, any moisture could throw off the sensor and make it do weird things.
If you notice any water or dirt on the panel, treat it like a touch screen. Don’t use any chemicals or soap to clean. Get a microfiber cloth and wipe gently. Also, use a little alcohol if needed. I use a hand sanitizer (without lotion) as it is easy to do a quick squirt to wipe.
The next solution is to check the inside of the thermostat where the sensors are. To do this, gently pull the face cover plate on the thermostat. Be careful not to wobble too much, as it could damage one of the plastic pins.
Where the buttons are on the face plate, you will see 3 square areas with foam. Those pieces operate the pin sensors you see on the thermostat control board.
Those foam pieces on the panel face can sometimes get bunched up and cause the sensors to function incorrectly. To fix it, get some tweezers and a small screwdriver, and try to unbunch the foam. They should be almost to the face of the plastic with a small slit down the middle for the metal sensor pin to go in.
Incorrect Temperature Readings
Another problem reported is inconsistent or incorrect temperature readings.
The manual says this thermostat is accurate to plus or minus two degrees. There are many reports of people getting up to ten degrees of difference.
Solution
If you get a drastic difference in temperature readings, the first step is to do a hard reset. Review the instructions above for a reset sequence. If that does not work, the sensors could malfunction, and the thermostat may need to be replaced.
How to change Dometic thermostat from Celsius to Fahrenheit
If you want to toggle between Celsius and Fahrenheit on your Dometic thermostat, the owner’s manual says to simultaneously hold the “up” and the “down” buttons.
Dometic Thermostat Replacement
I think it is safe to say that the Dometic 3 button thermostat is not the best RV thermostat on the market. It’s complicated enough that if anything goes wrong with it, the main camper will likely be unable to troubleshoot.
Many people have voiced their opinion that instead of fixing their domestic thermostat, they prefer to replace RV thermostat upgrade, like a Honeywell thermostat. The issue is that the basic thermostat will not work with the current thermostat wiring done with the domestic.
More basic thermostats have several low voltage wiring and are battery-powered. Just replacing without considering the wiring diagram will cause a problem. Even a basic programmable thermostat will likely not work.
Another thing to consider is replacing a different Dometic thermostat with similar wiring. Dometic makes a programmable thermostat that functions similarly to the separate control box to operate the Dometic RV air conditioner and furnace. These units should have the same wiring in your trailer. Other thermostats are the Dometic ccc2 Thermostat for dual zone and Single Zone LCD Thermostat if you have a single zone. The ccc 2 thermostat has buttons vs touch sensors and seems to be more reliable.
Your best bet is to contact Dometic Corporation and see what is available as a replacement using the same wires as your current system. they can pull up your thermostat wiring diagram and see which Dometic digital thermostat will work. I hear it can sometimes be a challenge to deal with Domestic, so if you have a hard time, also try your local RV dealer, who may have more pull and expertise in getting this info.
Final Thoughts
The Dometic 3 button thermostat problems can be frustrating when you only want to have a functioning air conditioner or RV furnace. Even more frustrating is that simple analog thermostats can do the job easier and reliably. The complex nature of the 3 button lends itself to communication problems and issues with its touch screen buttons. Sometimes a system reset works. But sometimes that doesn’t do anything, and a replacement is necessary.
Tony is an avid camper and RV traveler. He fell in love with camping on his first RV trip with his wife over 25 years ago. Tony loves sharing lessons learned and tips about RV maintenance and safe traveling.
