Community Forums

ebprod · 03-18-2012, 09:17 PM

My Duo-therm thermostat has stopped working. I have two of them, but only the front one has stopped. I can still run the rear air conditioner with the back thermostat.

I have attached pictures of both of them. The one that doesn't work is the one with the green lights and slider switches (on the left).

I haven't used it since last fall, so I don't know when the trouble began. I just replaced my CO/propane detectors, so I was messing around with the wires back there. Also, my house battery was dead, but that is working now.

The thermostat doesn't do anything when I turn on the power switch. The wires feeding the thermostat have power, and I can run the furnace by touching the two blue wires together. It is still plugged into the ribbon cable.

Can this thermostat be replaced? Or is the problem somewhere else?

-Joel

"007" · 03-18-2012, 09:31 PM

I'd remove them from wall and clean the wire plugs to them, you may just have some oxidation and they need to be cleaned.
If its the five button you need an exact replacement to control the AC systems and furnace control boards.
Here is a 5 button trouble guide.

ebprod · 03-18-2012, 09:52 PM

The thermostat with the five buttons works fine. It is the other one that is giving me trouble.

-Joel

Quote:

Originally Posted by 007";1118112]
If its the five button you need an exact replacement to control the AC systems and furnace control boards.
Here is a [B][URL="http://bryantrv.com/docs2/docs/ccc5.pdf

5 button trouble guide[/URL][/B].

RVhauler · 03-18-2012, 10:25 PM

Same holds true for that stat also in checking for loose connectors/corrosion

"007" · 03-18-2012, 10:28 PM

Is that one for a separate AC ?
Here are some links that may help with older thermostat.

ebprod · 03-18-2012, 10:47 PM

I'm not sure how they are set up. Each thermostat seems to control it's own air conditioner. The rear thermostat has a button for "zone", but I don't know what it does.

The MH is a 38" 1994 Kountry Aire.

I am going to try some contact cleaner on it, but I won't have a chance until next weekend. Hopefully the on/off switch is just dirty.

I have read that I can't just replace the thermostat, but there is a control box that needs to be replace as well. Anyone have any experience with this one?

-Joel

Quote:

Originally Posted by "007"

Is that one for a separate AC ?

ebprod · 03-19-2012, 09:55 AM

I haven't had a chance to use cleaner on the contacts yet. However, looking at worst case scenario- it appears that I would need to replace the control box inside the air conditioner. I think this is what I would need: Dometic 3107541.009 Analog Controls Thermostat

How does one get to the air conditioner to replace the box? Do you go at it from the inside, or from the roof? Does it involve removing the air conditioner?

-Joel

Magic · 03-19-2012, 10:16 AM

Hi,
I have the 5 button (using 2 zones with 2 ACs, 2heat pumps, and 1 furnace) and had to have the "mother board" in the front AC replaced I think I know why they call it a mother board as the total for the job was $375.00 ($175.00 for the board and 200.00 in labor). The tech also said the Duo-therm is changing the switches and doesn't have a new switch or board for units with heat pumps in them so I should be glad it was the mother board and not the switch. This was last month when it happened.

ebprod · 03-19-2012, 12:30 PM

Mine has a "heat strip". Is that different than a "heat pump"?

Also, my rear thermostat has five buttons. I think the older version had four. Since my motorhome is a 1994, would this mean that mine was upgraded at some point in the past?

-Joel

Quote:

Originally Posted by Magic

Hi,
I have the 5 button (using 2 zones with 2 ACs, 2heat pumps, and 1 furnace) and had to have the "mother board" in the front AC replaced I think I know why they call it a mother board as the total for the job was $375.00 ($175.00 for the board and 200.00 in labor). The tech also said the Duo-therm is changing the switches and doesn't have a new switch or board for units with heat pumps in them so I should be glad it was the mother board and not the switch. This was last month when it happened.

Magic · 03-20-2012, 09:35 AM

Hi Joe,
Yes, the heat strips are different. The strips are added to work just with the fans in the AC unit. The heat pumps are the AC and heat unit. My understanding is that the pump in the AC mode draws the cold part of the air into the motorhome and discharges the warm. In heat mode, it does the opposite.
I'm sure there is someone on here that knows how and why, but that's how it was explained to me.

As far as the switch, I think your 5 button is a newer unit and a add on at some time. I think the 4 button units are the older ones. DAVE