Dometic digital thermostat

[time2roll]

Been wanting to go with a digital thermostat but I was not very excited about using the battery powered home units for the conversion. Then found out Dometic has a new thermostat and control board.

So if you have this thermostat:



And you want something like this:
(I fixed those extra holes BTW)



Here is the kit:

Dometic Single Zone LCD Control Kit w/ Thermostat White 3313189.000 $75

Here is the kit pictured:

clockwise from top left. freeze sensor, spade terminals to crimp onto your furnace control wires, wall thermostat, mounting screws, control box, wire harness.



This is the old box up in the air unit



Here is the new box. Much smaller should also allow better air flow through the inlet filter.



Old box with the gaggle of wires. Actually fairly simple.

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 old thermostat.

Everything is either cut or disconnected to remove the old box.



New box connected to romex



The kit comes with a wire harness to connect to 12v and the thermostat cable. Only three wires are used for the new thermostat. 12+, 12-, & one control wire. I used Red, Black, Orange as that matches the harness.

This is the new box with snap connectors:



The heater control wires connect to the two spade terminals on the left. Thermostat control harness snaps into the four pin middle connector. Freeze sensor on the two pin connector to the right. Romex goes in at the far right. Power and control to the air conditioner uses oem harness that plugs in on the back side.

Worked perfect right out of the box. Well OK I had to buy some spade connectors as the oem wire to the furnace was a larger size. And some crimp connectors (not included) to connect the 12v thermostat harness.

Here is the user manual for those that want more operating details:
Dometic single zone digital operating instructions


Inspired by member BuffaloIndian in this thread:
Anyone Replaced Dometic Thermostat: Analog to Digital?

[time2roll]

Pictures have been restored 11/24/2017 :B

Thanks for nothing Photobucket 😞

[olskool]

Yes 12V at the "12v" terminal on thermostat. I unhooked the battery before I left tonight. A few forums said that's how you reset it. I will be calling Dometic and talking to them tomorrow.

[time2roll]

If you verified 12v power right on the 12v +- terminals of the thermostat with correct polarity it should power up the display when you touch the buttons.

[olskool]

Update - Got it wired. I was able to reroute the wires up to the control box. Routed the 2 furnace wires up from the old thermostat. Routed the 12V+ up to it and the routed the 3 wires that hook to the thermostat. Have it all hooked up but the thermostat doesn't display. I checked power and there is 12V at the small 12V screw so I know power is reaching the thermostat. I checked continuity between the 3 wires back to the control box and there is. No display. I have the Dometic Capacitive Touch thermostat. I called Dometic - No help at all. I think the thermostat is bad since I do not get a display at all. Any ideas?

[olskool]

No, tried and tugged on the existing ribbon wire and it must be secured. What I am thinking is this. If you look at the thermostat you see the 4 wire plug. 2 blue 1 red and 1 black. That's the wires I need to get to the control box. That there is my 12v+, 12v- and my 2 blue furnace wires. I don't have any choice but to do a partial disassembly inside and get those wires up. I will also need the 12v+ constant wires. That I will have to figure out as I don't have that. I will have to run that from the 12V distribution block.

[time2roll]

Any possibility you could use the ribbon to pull real wire up to the control box?

[olskool]

The ribbon is the only wiring that runs up the control box a/c unit. The 4 wire connecter disappears somewhere else. I would have to get a schematic from Holiday Rambler but they have been bought and sold 3 or 4 times now.

[time2roll]

Yes that looks very different than what is covered in this thread.

I would guess the 4 wire connector receives 12v power on the black/red and signals the furnace on the blue wires. Ribbon must control the air conditioner.

I think you need a technician familiar with your system to help make this work. Does not seems very plug and play to me.

If you are willing to cut the connector off the old thermostat you could get the 12v power you need. Measure if there is 12v in the wall connector. I think if you jumper the two blue wires together the furnace should run. But you would need to use some existing wire to get the furnace signal from the box down to the two blue wires. And use one wire to get the digital signal up to the box. But I am guessing a bit if this is even possible. Those ribbon wires might work but look thin.

[olskool]

Here's the picture of it.

[time2roll]

Exactly what thermostat are you replacing?
Is it the same as shown first in the original post?

[olskool]

I called Dometic and talked with them and he said I would need Kit #3313189.000 for my set up. So I ordered it but it looks a lot more complicated than others have posted. First, I do not have 12+ wires at my roof top a/c unit. All I have are the 120V, the plug from a/c (6 wires,) and the freeze sensor and the ribbon from the thermostat. There aren't any wires from the furnace or elsewhere. The kit wants 12+ to hook up to it but I don't have that. I don't have the 2 furnace wires either that are needed to hook up. The back of my thermostat had the ribbon connector and another connector with 4 wires from it. I have no idea where the 4 wires go. The ribbon came out by the old analog box in the a/c. I really don't want to have to disassemble half the interior to route new wiring. Thoughts anyone?

[Chris_Bryant]

KeithE wrote:
Hello! I wonder if anyone can help me with a problem I've been unable to solve for over a month. I recently purchased a new Dometic 15k BTU A/C and new LCD thermostat. My coach has an existing furnace that needs to be wired in to the new control box. The new control box has 2 blue/white wires to connect to (and control) the furnace. The furnace has 2 wires (a red and a white). I presume the blue/white wires get connected to the red and white wires, but ... does it matter which gets connected to which? I'm utterly desperate to figure this out: Dometic is useless, the instructions are useless. Thank you so much for any help you can give!

It doesn't matter- the two wires on the control box simply go to a relay- open or closed.

[KeithE]

Hello! I wonder if anyone can help me with a problem I've been unable to solve for over a month. I recently purchased a new Dometic 15k BTU A/C and new LCD thermostat. My coach has an existing furnace that needs to be wired in to the new control box. The new control box has 2 blue/white wires to connect to (and control) the furnace. The furnace has 2 wires (a red and a white). I presume the blue/white wires get connected to the red and white wires, but ... does it matter which gets connected to which? I'm utterly desperate to figure this out: Dometic is useless, the instructions are useless. Thank you so much for any help you can give!

[olskool]

Single roof top a/c and single furnace.