How to tame the Dometic digital thermostat

Sometimes seemingly simple items can be the most infuriating. One example we hear about frequently is the Dometic digital thermostat that is found in many Airstreams—it has a reputation for being a little cranky.

We're talking about the black or white thermostat that controls your air conditioner, furnace, and heat pump. If you have one, the buttons may be a little different from the one in the picture, but they all work roughly the same. It's officially called the Dometic Comfort Control Center 2 Thermostat, or "CCC2."

The manual that comes with this gizmo says proudly "Your Dometic CCC 2 thermostat has been designed for ease of operation" — which, ironically, is followed by 12 pages of explanation on how to use it. 

This thermostat has features laden upon features, enabling control of air conditioner, furnace, heat pump, fans, clock and light. You can program it to change mode and temperature by time of day or depending on temperature, in up to four zones, and in Celsius or Fahrenheit. It even has two different ways to turn it off. The only thing it doesn't do is sing Christmas carols.

This plethora of features creates complexity – which is what can lead to confusion. Let's look at a few of the most common problems that Airstreamers ask us about, and how to fix them. 

MODE confusion and what the acronyms mean

Intuitively, you might think a button labeled START would be the first step to use or programming this system. Actually, the MODE button is the key to everything. By pressing MODE, you can toggle through various possible methods of climate control: COOL, FURN, HP, HS, FAN, AUTO, and OFF–although your Airstream may not offer all of these options.

Let's start with the most commonly used modes: air conditioning and furnace.

Push the MODE button, choose the mode you want (COOL = air conditioning, FURN = furnace), then choose the temperature you want using the up and down arrows. Simple enough.

But wait, there's more!

The HP mode is for Heat Pump, which basically means your air conditioner operating in reverse to produce warm air instead of cold. Not all Airstreams have this option. It only works above freezing temps (and not very well below about 40°F), so its use is limited.

If your Airstream doesn't have an HP mode, it might have an HS, which means Heat Strip. A Heat Strip is a little electrical heater built into the air conditioner. Unlike the heat pump, the heat strip works at all temperatures. That's a plus. But since it blows warm air from the ceiling, your feet will still tend to remain cold so bring fuzzy socks if you plan to use the Heat Strip.

FAN mode just makes the fan blow recirculating air without either heat or cooling. It's not very useful. The rooftop Fantastic Vents work a lot better for ventilation.

Finally, there's AUTO mode. This allows you to program the thermostat to run the heat when it's cold in the morning and then switch over to air conditioning when it gets hot. It's a potentially powerful feature but dizzyingly complicated to program. If you don't love technology (or reading detailed instructions), I recommend you steer clear of AUTO mode, and just switch from heating to cooling by yourself.

Ok, I've chosen the mode. What next?

Once you are in any of the modes, pick the fan speed–LOW, MED, HIGH, or AUTO. Do this by poking the FAN button until it displays the speed you want. Honestly, I think it's best to keep things simple and leave the fan set to AUTO. The thermostat will determine a good fan speed, depending on the temperature. 

"I set it to 'COOL' but nothing happened..?"

The thermostat won't let the air conditioner turn on for about two minutes after you choose COOL. That's to protect the compressor. So you have to be patient. There's a little hourglass icon in the display that will go away when the air conditioner is ready.

The same is true for HP (heat pump) mode. 

"I turned it 'off' but it isn't..?"

The final mode choice is OFF. That's kind of weird, since there's a power button as well. (That's the button on the top left—the one with a circle that has a stem on top.) You'll probably never use OFF mode, unless you are getting fancy with programming (which we'll talk about in a moment).

ZONE confusion

If your Airstream has two air conditioners, you'll have two zones. Pressing the ZONE button will toggle between Zone 1 and Zone 2. This allows you to run one or both air conditioners, but it can be confusing because the furnace is only in one of those zones. If you can't get to the mode you want, try the other zone.

If you had two zones that displayed, but suddenly only have one, check the power coming into the trailer. If the 50-amp power isn't wired correctly, or you are plugged into a 30-amp outlet, one of the zones will be unavailable.

In other words, you must be connected to 50-amp power to cool both Zone 1 and Zone 2 simultaneously. 

And yes, you can set the temperature in each zone separately. You can even run the heat in one zone and the air conditioning in the other, although it doesn't really make sense to have such a feature in a 200 square foot space.

Error messages

There's a page in the Dometic manual that describes all the error messages, but the most common one is an “E7” error code. This code simply means that the thermostat was set to run the air conditioning (or heat pump) but couldn’t. Usually it is because there was no AC power to the Airstream. To fix this: plug in the Airstream (or reset the circuit breaker if it popped off) then power the thermostat off and on to reset it.

Stuck in programming purgatory?

If you find, as occasionally happens, that none of the buttons are working as expected, you may have accidentally entered "program mode." You'll know you are in program mode if "PROG 1" or "PROG 2" is blinking in the display. To get out of this mode, push and hold the PROGRAM button for 3 seconds and it will go back to normal. Consider this your get-out-of-purgatory free card.

Really, really stuck?

Nothing in this blog post seem to solve your problem? Thermostat still misbehaving? You can assert your superiority over this little plastic martinet by forcing a total reboot. 

The secret to showing your defiant digital helper who's boss is to press and hold the MODE and ZONE buttons simultaneously. When the display shows "IniT" you can release the buttons. Then press the Power button.

Now that you've tamed the unit into submission, press MODE to start all over again.

15 comments

JOHN W GREEN

JOHN W GREEN

I replaced my Dometic thermostat with the Micro-Air Easy Touch digital wi-fi/bluetooth thermostat. It’s a “plug ’n play” installation. Very easy to understand and I have remote control of all HVAC functions when I’m away from the Airstream. Look for the Micro-Air booth at the Freyburg, ME International Rally. They will have the thermostat on sale with a discount.

Alan M Kessler

Alan M Kessler

New replacement solves all problems plus a lot better.
Micro-Air easy touch rv thermostat SY-389-X50

Pete Iverson

Pete Iverson

Good piece Rich. I have found that the FAN needs to be set to AUTO in order for the FURN to work properly. Also, could you do a similar piece on that HiFi system called Clarion? It is more frustrating than the CCC2.

Donald Wright

Donald Wright

Thank you Rich, I will try an figure out how to print this.

David Byrnes

David Byrnes

Thanks for your guidance on using the digital thermostat. We purchase the AS from the first owners and none of the guidebooks were included. As you can imagine the first time using the system for heat…..it took us 20 mins to figure out how to make it run!
Great write up and as always, a big thank you.

Rebecca Barnes

Rebecca Barnes

Such a helpful article! I had somehow switched our thermostat to the Program mode and could not figure out how to get out of it! And of course I could not find our instruction book. Fortunately, this happened just a week or two before scheduled warranty work at the Mothership in Jackson Center. My husband reported to them that the thermostat was not working and, miraculously, when we picked it up it was working just fine. I bet they know the reboot trick!

Daren Beaudo

Daren Beaudo

I was glad to know I had figured this out. What really frustrates me though is the difference in 1) temperature sensitivities (do you know where the sensors are?) and 2) one unit sure seems to blow better than the other. I don’t know if that’s intentional or a function of my unit. I’ve had them checked and they supposedly work.

RD VanOrsdale

RD VanOrsdale

So, where do I go to get schooled on how to program the thermostat? And, where do I go to find out which is zone 1 and which is zone2?

Dan

Dan

Concur with Pete. Please, do a similar piece on that HiFi system called Clarion? It is more frustrating than the CCC2.

Jo Reeves

Jo Reeves

I always have to turn off the furnace using ‘off’ mode. If I use the power button to turn it off my sail switch never works again and the dealer has to replace it. The furnace doesn’t cut off instantly when you use ‘off’ mode so it must cycle through everything to leave the sail switch in the correct position to work the next time.

Ed Fincher

Ed Fincher

This article hit with perfect timing ,.. the night before I had been searching the net how to clear the programming mode on my Airstream. Great job Guys 👍

Larry Brodsky

Larry Brodsky

Yeah, I agree with others. The only logical solution is the Micro-Air thermostat with more functionality, more intuitive, more updates and, best of all, you can sit in a different part of the trailer and control it while your spouse is sleeping!

Bob Graham

Bob Graham

Thanks to Rich for the informative articles. I echo Daren Beaudo’s frustration with the temperature sensitivity. I’ve mounted a thermometer next to the thermostat panel, and the temperature measured by the thermostat (push the “inside temp” button) bears little resemblance to the actual temperature. It is as much as 20 degrees off, but is not consistent; sometimes high, sometimes low, and sometimes almost correct. We can set the furnace to 60 degrees and get cooked at 80 degrees, or chilled at 50. Of course, the dealer can’t find anything wrong with it. So, how can I find where the sensor is located? Perhaps I could replace it or relocate it. I already replaced the thermostat panel, and the new one behaves just like the original.

Dorsey Richardson

Dorsey Richardson

Bookmarked this one. Thanks, Rich. I also would like to know where Zone 1 and Zone 2 are located. Simple question…can’t find the answer anywhere it seems…

Craig Fetty

Craig Fetty

Ditto Pete Iverson’s comment on Clarion.

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