Thermostat Failure

[Rusty Bear]

I have a RV Comfort.ZC AM7812H thermostat that locks up with 00 showing. That causes shut down prevents any change or restart with the controls until it is reset. Resetting is accomplished by temporarily pulling the fuse for the thermostat (or shutting down the complete 12 vdc source temporarily).

Now the thermostat will not reset any longer.
It appears that this model may have been discontinued and I am unable to find a replacement thermostat.

Has anyone found a replacement thermostat or another model that would work in our coach.

[Janet and Todd]

Dometic 3314082 011 Comfort Control Center II Digital RV Thermostat | eBay


I wonder I this one would work? My Comfort.ZC has been erratic since the day it was put in. Sometimes it refuses to change zones.

[DrDaveMA]

I switched to this one from Dometic, called "Control Comfort Center 2 Thermostat " (model #3314080.xxx without dehumidifier) it is programmable, there is also a model that will control dehumidification. I have it set for, Cool, HP, Aqua Hot, Auto and Fan Only. It is set for 2 zones, although It will do up to 4. The Auto setting switches from Heat Pump to AC depending upon the temperature. When we go out and leave Fenway alone in the coach I use Auto and set the fan to low, that way the fan provides "white noise" so there is no barking if there is a noise outside, he just doesn't hear it.

It can be programmed to change temperature or mode (cool, heat, etc) by time, although I do not use it. There is also a setting for Heat Strip if you have one. My feeling is this a great replacement for the original thermostat, I like it!


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Dave, Bobbi and Fenway

[Janet and Todd]

Dave,


Any pitfalls to installing and programming the Dometic thermostat? Any compatibility issues with the Roof Heat Pumps?

[Rusty Bear]

Did a wiring diagram come with the Dometic? Also has anyone have a wiring diagram for the RV Comfort.ZC AM7812H and know where all the wiring runs bu color?

[Dave Fernandez]

When new A/C Heat pumps were installed last year a new Dometic Comfort Center Thermostat was installed . It uses the same data cable as the old thermostat used. It does more than the old one. :thumbup: It has the time, temperature, and other settings which makes it better then the old one. I like it better I just must remember how to program it every time I use it.

[DrDaveMA]

Janet, Todd, as Dave F says, no issues with installation and as long as you keep the manual handy, no problems with programming. Actually it is very intuitive.


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Dave, Bobbi and Fenway

[MKelley]

Dave what is :thumbup:?

[Janet and Todd]

Thanks Dave and DrDaveMA.

[Janet and Todd]

I have RVP A/C and Heat Pumps on the roof. Dometic says their thermostat is not compatible with RVP products so Rusty Bear, if you find a replacement for your RV Comfort.ZC, please let me know as I am looking to replace mine too. In addition to refusing to switch zones, the thermostat is causing the Hydro Hot to quick cycle zone 2 heat exchangers off then back on.

[Janet and Todd]

I received this document from RVC Products:


Reset Procedure for Zone Control


Signal Disruption






The problem you are experiencing is usually caused by one or more of the twelve volt components in


your coach. The most common would be a bad ballast on a fluorescent light. If this is the case, you


will need to leave the light off until the fixture can be replaced. Follow the directions below to locate


the issue.


1. Make sure that all upper units, ceiling assemblies and control boxes are installed correctly and


12 volt power is on.


2. Place the thermostat slide switch in the “OFF” position.


3. Remove the thermostat cover.


4. Remove the fuse for five minutes.


5. While the fuse is out, turn off all the twelve volt lights, unplug anything plugged into a twelve


volt outlet, make sure you turn off anything else you can that is twelve volts without shutting


down all the twelve volts for the coach.


6. Reinstall the fuse and wait another five minutes. NOTE: Do not touch any buttons or switches




during this time, doing so will cause the thermostat to lock out immediately and you will have


to start over.


7. Once the thermostat is back to running normal, go back through everything you can in the


twelve volt circuit in the coach, turning them on to see if they affect the thermostat. When you


find what is causing the problem, the thermostat will do something out of the norm. Usually the


thermostat will show “00”, a phantom zone, dim way down, or even go blank. If the thermostat


does any of these “out of the norm” displays, then you know that the component you just turned


on is causing the problem.


Known Causes:


(it will always be in the twelve volt circuit, so look for these components to be plugged into 12vdc)


Cell Phone Chargers


Electric Shavers


Brake Buddy System


Fantastic Fan


AC Ripple (usually a filtering issue at the converter)


Computers

[Marca]

Any update on either a fix or a replacement thermostat? Has anyone tried running a new DC power wire from the DC power supply fuse panel in the hallway to the thermostat? This would be the wire connected to the one amp fuse for the thermostat that I pull and reset when this happens. Could that be picking up interference from a wire close to it?

[Rusty Bear]

Sorry for not updating. Quick update My Air Conditioners are Coleman and the Dometic thermostat will not work. I was able to find a direct replacement ZC AM7812H thermostat online and after installing new thermostat (unplug old thermostat and plug in new thermostat) everything is working as it should.

[Marca]

Rusty Bear,
Thanks for the info. Do you know where you purchased the new one from? Does it have the same look as the old one or is it different? I would like to get a new one but want to make sure I get the correct model since they are non-returnable. Several years ago we purchased a new one through Camping World but it didn't work any better than the old one. They let us return it. Getting a little tired of dealing with its unpredictability.
I appreciate your help.