Community Forums

TillRodsFly · 09-26-2015, 08:45 AM

Hey fellow Rv'ers! I have a 2001 Holiday Rambler Endeavor that has the 5 button Comfort Control thermostat. I went to try to turn both A/Cs on not long ago and when I switch to mode 2 that controls the rear A/C, the screen is blank and can't get he rear A/C or fan to turn on. I'm hoping that the thermostat just went bad. The rear A/C was working great the last time I used it (about a month prior). Has anyone else had this issue? Any help would be greatly appreciated. Thanks!

Paramedic 1 · 09-26-2015, 08:57 AM

I have the same thermostat in our Allegro Bus but NO issues. I am thinking maybe there is a battery in the unit???.....or maybe you popped a 12 volt fuse somewhere???....check all your fuses and I may go out to our coach and see if there is a battery in it??.....
I just went out and checked....NO battery....I am thinking a fuse somewhere....good luck....let us know what you find.

deandec · 09-26-2015, 09:06 AM

Reset your AC breaker for that AC?

Check that the 120v wiring is connected properly at the second AC and has power with your multimeter.

If thermostat works it has 12v power.

Gary RVRoamer · 09-26-2015, 09:07 AM

I'm guessing you mean Zone 2 rather than Mode 2?

There are two thermostats with the name "Comfort Control", a Duotherm and an Atwood. Slightly different, so which one do you have? And do you have the Op manual for it? If not, you can download one online.

Try disconnecting & reconnecting the wires on the back of the thermostat. May be a bad connection there.

There is also a reset procedure that may work, but need to know which t-stat model you have. Most likely it resets like this:
Turn t-stat Off. Press and hold both Mode & Zone buttons and then turn On. It should display something like "Init" and re-connect to all the available zones.

TillRodsFly · 09-26-2015, 09:11 AM

Thank you for your reply.

Unfortunately I won't be back at the coach until tomorrow. I will definitely check all fuses. What is confusing and making me think it's a bad thermostat is that it controls everything else fine. It's just when I switch it to mode 2 for the rear A/C, then the screen turns blank. It's like the rear A/C doesn't exist anymore. It all worked great (rear A/C blew super cold) the last time I used it. (about a month prior)

TillRodsFly · 09-26-2015, 09:15 AM

Great info guys! Thanks! I will check and do everything suggested when I get back to it tomorrow. You are right Gary. I meant Zone 2. I'm 99.9% sure it's the Duo Therm.

MSHappyCampers · 09-26-2015, 09:37 AM

Quote:

Originally Posted by Gary RVRoamer

I'm guessing you mean Zone 2 rather than Mode 2?

There are two thermostats with the name "Comfort Control", a Duotherm and an Atwood. Slightly different, so which one do you have? And do you have the Op manual for it? If not, you can download one online.

Try disconnecting & reconnecting the wires on the back of the thermostat. May be a bad connection there.

There is also a reset procedure that may work, but need to know which t-stat model you have. Most likely it resets like this:
Turn t-stat Off. Press and hold both Mode & Zone buttons and then turn On. It should display something like "Init" and re-connect to all the available zones.

Just a little clarification to what Gary said. Continue to hold the two buttons in when you turn the power switch (the slide switch under the bottom) back on, then release them after a few seconds.

TillRodsFly · 09-28-2015, 08:23 PM

Hey guys. Just got to the mh tonight. I unplugged the thermostat and noticed some corrosion on the back side of the circuit board around where the plug is. I cleaned it the best I could with electronic cleaner. Plugged it back in and it showed the rear ac (temp settings ect) but the rear ac or fan still wouldn't turn on. It showed it for about 10 seconds then went blank again just like it did before.

I then tried the reset as mentioned and now it won't switch to zone 2 at all. Every time I hit zone, it stays on zone 1. I reset the rear ac breaker but couldn't find a fuse for it. Where do I go from here guys? I tried looking for a new thermostat figuring it would be worth the gamble to try that but I can't seem to find my exact model. It has 50-981501-A on the circuit board. ANY help would be greatly appreciated!!!!

dutchstr3884 · 09-28-2015, 11:20 PM

Seems to me that it could be that something in the Zone 2 AC is not working and because of that the thermostat can't "see" the AC. It may be time to go on the roof and remove the AC outer shroud and look for a breaker up there. Do you have the manual? Attached is a troubleshooting guide you may find helpful.
There is also a Dometic AC-Furnace Trouble Shooting Guide and a Dometic AC-Furnace Trouble Shooting Guide but they are too large to attach here. Do a web search for them. If you do not find them personal message me with an email address and I will send them to you.

Good luck