Both my roof AC unit quit working.I have line voltage to the AC units.I have a Duo Therm digital Thermostat, but it looks like its not getting power(no info on the stat).I replaced the stat , but nothing happened.Checked the fuse in the unit.Ran a new phone line type wire from the unit to the stat......nothing there either.Any info would be great......it's hot here....LOL

Circuit Breaker ? There may be 3 of them. At the pedestal/power receptacle, on your RV power panel and on your converter/inverter.

Is it getting 12 volt power to the control box?

It's getting power at the AC unit.I don't know about 12 volt power.........Don't know where to check that???

Remove the inside trim and you should have access to the control box.Wires include, 120vac, black pair to freeze sensor, bundle from thermostat, blue/white to control furnace, and some black/white paired wires that carry 12vdc.The 12v wires should be attached with a crimp connector to the harness. Get your voltmeter on those wires to check voltage.Paired white/black are 12v supply.Blue/white is control connection to furnace.Yellow is 120v power bundle.Black to the left is the freeze sensor.Brown is the bundle from the thermostat.Or maybe your Dometic is completely different.

That looks kinda like mine.I have 12 volt at the fuse, & the red wire.There is a circuit board in the box.Looks like one of the "phone" plugs it not looking too good.

Duo Therm roof A/C | Good Sam Community

27 Replies

cdl2
Explorer
Aug 21, 2014
I got the second module board installed.
Rear A/C is working.
I'm having trouble programing the T Stat.
I have two roof A/c units with electric strip heaters....& an LPG furnace.
The new T Stat is suppost to find all that.
cdl2
Explorer
Aug 19, 2014
I installed the new module board & the new T Stat.
Front air works again, but the rear air does not.
I called Dometic ......they told me I need a new module board in the rear A/C too. The new T Stat doesn't communicate with the old module board.
So I ordered an other new module board.
cdl2
Explorer
Aug 17, 2014
I ordered a module board & a T Stat.
Should be here in a few days.
The T State is an undated one to go with the new module board.
cdl2
Explorer
Aug 15, 2014
I checked & cleaned the ends & sockets.
Still no read out on the T Stat
cdl2
Explorer
Aug 15, 2014
Thanks......I'll take a closer look at the ends.
Chris_Bryant
Explorer II
Aug 14, 2014
cdl2 wrote:
Thanks for naming the cable for me......
I sure hope the data cable is good......replacing it would be a real challenge.

It's never the cable (almost)- it's the ends, which are standard RJ11 telephone ends- available at most home centers. Just pay attention to the polarity.
cdl2
Explorer
Aug 14, 2014
Thanks for naming the cable for me......
I sure hope the data cable is good......replacing it would be a real challenge.
Chris_Bryant
Explorer II
Aug 14, 2014
That is a Comfort Control Center if it uses a "phone type" cable. Keep in mind that is *not* a phone cable though, and a phone cable will not work- it is a data cable, and the polarities are reversed.
This is a data cable-
time2roll
Nomad
Aug 14, 2014
cdl2 wrote:
Module board & compatable T Stat are gonna cost $238.
wow my Dometic single LCD conversion was just $75 including control box and new thermostat.
You must have the high tech version.
PortWentworthSa
Explorer
Aug 14, 2014
I purchased a T Stat at Lowe's for $30.00 (house T-Stat) and it works fine for me. Of course I have straight AC (Ducted) and only one unit.

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Duo Therm roof A/C

27 Replies

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