Foretravel Owners' Forum

So we replaced both roof airs in Albuquerque (during a trip) last summer, along with the Comfort Control Center (installed the 5-button model).  Two new Duo-Therms. 

On three occasions since then, the CCC will lose power (as evidenced by a blank display), and both airs will shut off.  This has happened while connectied to shore power, and while using the generator.  Every time, the CCC will (at some point) regain power and airs come back on.  I can find no rhyme or reason to when this happens - one time the CCC had no display after just running the generator for about 3 minutes (only to come on about 30 minutes later); once, the airs were running for over 3 hours and then just shut off; and finally, over the weekend, they ran for 5 hours during our trip, all night while plugged into shore power, and then shut off the next morning while still on shore power - and came back on after starting the generator.

I'm very puzzled, and wondering if anyone has any thoughts?  Thanks!

It looks like a bad connector.  Look in the front AC and you will see a female to female connector. Replace that and see if that will help.  You can test it by pulling the wall unit and plugging it into the AC directly.

Thanks John. I'll get a new one and try that.

Did it ever work. If not you might have dip switches that will need to be adjusted up top.

John, I'll have to pick one up tomorrow and try it as the coach is in storage.  Unfortunately, since its so intermittent, I may not be able to tell if its fixed until we're in it for a few hours. Thanks again for the suggestion. As for the dip switches: it seems like if they weren't set right, the airs wouldn't ever function correctly- right? 

Yes that is why I asked if it had worked in the beginning.  I am still betting on a bad connector in the front AC. They are in series so if you lose one you lose both if it is the front one.

Both our furnaces quit working one time while we were heading north in cold weather. Found a local RV place in the 'net. I planned to buy a new controller. The store was closed. Shortly thereafter, all started working again. ??? The controller failed once, for about two hours, in three years. Sometimes the gremlins get you ... or it could be dirty or loose connectors.

I may have fiddled with some connectors between the failure and the "spontaneous healing." I don't remember. (It's funny how I remember more and more things that didn't happen :P , and have more difficulty remember what did happen.)

Hi Chris,

The usual delay time for the A/C compressor to start is around 3 minutes. This allows unloading of high start up pressure for the compressor.

Dometic no longer supports the Comfort Control Center 4 button thermostats and upgrading to a 5 button system is fairly expensive. Consequently most folks have their thermostat rebuilt when the four buttons go wacky or the power switch fails. For example, if either the fan or mode button are erratic then switching zones can be frustrating. I can help you with these problems.

The thermostat reset procedure seems to solve most erratic problems. If the word furnace does not show on the thermostat display you might look for blown fuse for the furnace(s) - a 12 volt signal from there is required for it to be appear.

Should you decide trouble shoot bad connections by using another 'phone type' cable, examine the ends first, being careful to observe the same order of the four colors in the two plugs. Most available 'telephone' cables have their plug wire colors in the opposite order which will not work with the Dometic 4 button systems.

Good luck, 
Jim

2002 U320 42'

308-440-5154

Hi,

Have you considered doing a thermostat "reset "...sometimes the IC inside gets scrambled and loses it's mind.. Advise if you need the procedure.

Jim

308-440-5154

Duo Therm Troubleshooting Manual
Duo Therm 5 Button 3109228.001 Troubleshooting (http://beamalarm.com/Documents/duo_therm_5_button_3109228.001_troubleshooting.html)

   I will share my experience in case it may be of help. I had the exact same problem but mine is a 4 button unit. If the 5 button unit still has the slide on/off switch on the bottom that could be the problem. Mine would go blank and shut off. If I fiddled with the on/off switch it would come back on. It turned out to be a cold solder joint on the pcb going to that switch. I re soldered the connections and it has been fine ever since. Hope this is helpful.

Regards , Mark

Thanks everyone for all the troubleshooting suggestions!  I think I'll replace the female-female connector, and then do a system reset as well and see how it goes - and report back. 

Jim, we upgraded to the 5-button thermostat and really like it much better.  It just made sense to upgrade everything when we were installing the new A/C's.  When the CCC has power, everything works perfectly.

Thank you, Mark - I'll check that too.

And Barry - thanks for the troubleshooting guide. 

Chris,

You might check the phone type plugs at the thermostat and at the A/Cs. Tapping or shaking the un-mounted thermostat and wiggling all the wires may produce a clue. Sometimes the tiny contact wires in the receptacle come out of their slots or aren't making good contact.  Also re-crimp or replace (observe wire color orientation) the plug(s) on the cables with the special tool for attaching them. The reset procedure might be the first thing to do in case the thermostat's IC is reading corrupted memory.

Maybe these will be helpful:

how to do a system reset on the dometic 5 button control. - RV Forums - (http://www.myrvparks.com/forums/showthread.php?t=2936)

http://bryantrv.com/docs2/docs/ccc5.pdf (http://bryantrv.com/docs2/docs/ccc5.pdf) 
Jim

2002 U320 42'

If I remember correctly the female double connector is not the same as a standard telephone doubleconnector, but the rear ac should have one that is not being used which you could substitute for one of the front ones and see if that makes a difference. Also check the 12 volt connection at the front ac as I think it is the red for 12 volt + and black for the 12 volt -. Another thing to check is if having a flourscent light on has any bearing on the ac problem as a bad ballast can send out bad rf to the ac's and cause them to not work.

Interesting thought, red tractor.  I don't remember if we had any flourescent lights on or not but will pay attention to that. 

I bought a female-female telephone coupler at Radio Shack and assumed that's what I needed; I'll see if it's different when I go to the coach to swap it out.  I think I do remember one on the rear a/c.  Thanks.

I have worked on several country coaches that had that problem with the lights and my friend also had a 99 Monaco diplomat that was having problems with his dometic roof ac's with the comfort control center that was caused by a bad ballast on one of his lights, nearly drove us crazy finding that one. His ac's only acted up when his wife was cooking as the bad light was in the kitchen

Possibly the power switch on the Comfort Control Center has become has a cold solder joint to the circuit board. With the unit removed from the wall, wiggle the switch and observe the solder pads.

Jim

2002 U320

Just closing the loop on this thread...turns out, the circuit board in the front unit (topside, under the shround) had a bad (loose) connection.  This is where the Comfort Control gets its 12V power.  Cutting Edge RV in Baytown was able to diagnose and repair it in less than an hour.  Thanks again for the referral, Rudy!