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Topic: Dometic digital thermostat to Honeywell

Posted By: ouchkernel on 11/21/16 03:53pm


Has anyone had any luck swapping out a dometic digital thermostat(3-wire) for a honeywell or any other brand? Seem dometic introduced a digital interface for controlling a/c and furnace. I am not sure its even possible to easily replace the thermostat without replacing the digital interface with analog.

Posted By: Chris Bryant on 11/21/16 04:08pm

Not possible, but Dometic does have a somewhat easier t-stat to use-, but the communications is proprietary digital.

-- Chris Bryant

Posted By: ouchkernel on 11/21/16 04:12pm

[quote=Chris Bryant]Not possible, but Dometic does have a somewhat easier t-stat to use- [url], but the communications is proprietary digital.[/quote] That really sucks...

Note: Due to invalid formatting, all formatting has been ignored.

Posted By: time2roll on 11/21/16 04:36pm

What issue are you trying to resolve?

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Posted By: ouchkernel on 11/21/16 04:40pm

time2roll wrote:

What issue are you trying to resolve?

Trying to get a more accurate thermostat. Ours has a 5-10 degree difference.

Posted By: time2roll on 11/21/16 05:04pm

Is that the temperature swing? Or is it just 5 or 10 too high or low?

Mine seems to hold a temperature fairly good but is off somewhat to our indoor weather station attached just above. Mine seems better when cooling but the heat it lets drift a bit low before it calls the furnace.

I had converted mine to the dometic single digital from the analog slider version and the digital is way better but not as good as my home thermostat.

Had not seen the new version posted by Chris above. For $25 I may get the new one to solve an illumination issue. Might even behave better for heating and cooling.

Posted By: ScottG on 11/21/16 05:19pm

Does your current stat only have three wires total? If so then I dont know.
If it has 5 or 6 then yes, it is easily done and many of us on this forum have done so. The only minor issue is you have to add a switch for the two speeds of your AC unit. Or you can hard wire it for either hi or lo.
Get one of the microprocessor controlled stats it will keep your temps dead on. I used one made by Lux. Link

* This post was edited 11/21/16 05:47pm by ScottG *

Posted By: Blacklane on 11/24/16 04:58pm

Three wires? Can you describe what they do or maybe what color each is?

It's quite likely that you can install a Honeywell thermostat. The 3000 series and 5000 series (and maybe others) non-programable units should be fine. They all have internal battery power (2 AA batteries). There are many other brands that are similar.

The only thing any thermostat does is close a switch at the right temperature. Electronic thermostats do that with relays instead of mechanical switches. The only thing special about RV digital thermostats is that they operate on 12vdc instead of 24vac like home thermostats use. The self-contained digital ones, like Honeywell, don't use any external power, so it doesn't matter. They use internal batteries.

You need to connect the +12v wire to the thermostat (R) terminal.
The wire to the furnace connects to the (W) terminal.

If you have a ground wire, don't use it.
If you have a fan wire, it connects to the G terminal.
If you have an A/C wire, it connects to the Y terminal.

You will also have to go through a short programming set-up.

Of course, you will have to replace the batteries regularly to prevent leakage and internal damage.

EDIT: After reading the posts below and doing a little more research, I can see that this is completely wrong. Disregard everything in this post. There IS something different about a Dometic 3-wire thermostat: a separate control box. It doesn't make economic sense to add a bunch of wires to use a traditional thermostat.

* This post was last edited 11/25/16 09:26am by Blacklane *

Posted By: time2roll on 11/24/16 10:58pm

Three wires on these include +- 12v power and a signal wire. No worky with home style thermostat.

Posted By: jetcare on 11/25/16 06:30am

You have the newer Single Zone Dometic digital thermostat that is communicating with a control box (gray in color) located behind the ceiling assembly filter. As you said, 12V+, 12V- and comm. You will not be able to use a different style thermostat unless you revert back to an older style control box and run more wires to the thermostat.

I find the Dometic digital thermostat to be very accurate. You need to replace the Dometic digital thermostat and see if your issue goes away.

Dometic PN: 3313192.000 for white and PN: 3313192.019 for black. Only $30-$35.

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Posted By: MrWizard on 11/28/16 11:50pm

Maybe one of these two ?

Dometic Five Button zone control

Dometic Comfort Air Thermostat

I can explain it to you.
But I Can Not understand it for you !


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Posted By: SCClockDr on 11/29/16 02:45pm

Or this one:

George & Cathy
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ETCS (ss) USN Ret

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