need some guidance wiring a digital thermostat

[esty]

we bought a travel trailer that had very little use but did come with a few issues we're trying to resolve...we got the DC power problem sorted out thanks to westend in MN for the how to

the thermostat for the Coleman Mach Roof Top Unit had been pulled off the wall when we got it...we've read a lot about using a digital thermostats which we bought at Amazon...it's a Honeywell RTH111B H/C Digital Manual Thermostat...

i've included pictures of the control board in the ceiling fixture inside the trailer along with pics of the inside of the thermostat and the wires out of the wall where the original thermostat used to be....also we will not use the gas heat, all we want and need is the a/c wired to the thermostat...

as much as i've read, i still am not sure what wires in the wall go to which terminals in the thermostat just to get the a/c and fan working....any help will be greatly appreciated

also, it's my understanding that no 12V power is necessary to the new digital thermostat because it uses batteries


the control board inside the camper in the ceiling


thermostat wires stubbed out of wall


wire terminals inside thermostat



i'm curious...what's the "freeze" terminal with the 2 white wires for on the control board...

[budwich]

I think you could just try following the labels as opposed to the color... ie. connect B to B, Y to Y and G to GH (that is high speed fan). See if it works but unlikely... I think you need a bit more in terms of wiring depending on what the coleman control board has in its design.

As for the "not needing 24v", that is basically true BUT, there are two reasons for the 24v part, one for operating the thermostat which the internal battery will provide and the other is to operate relays in the control system of the AC. If you don't provide some form of power either thru the thermostat (usually) or directly to the controller (then using thermostat to switch grounds), your controller in the AC won't work.

As other have suggested, you should try contacting coleman to get wiring information for the control board which will likely solve your issue.

This site might get you some info RVtechlibrary.com

[Dick_B]

Before giving up I'd next try contacting the manufacturer. This may be a start http://www.airxcel.com/coleman-mach
It would probably be good to have the a/c model number and s/n before calling.

[esty]

Dick_B wrote:
Wild guess but could it be wired for two A/C units?
I think for starters I would try to match up the wires at the t/s with the wires in the ceiling fixture ie do a continuity check. Hopefully that would eliminate half of the wires to deal with.

there is continuity in the wires attached to the control board and the wires hanging out of the wall - to be attached to the t-stat

my question is, which terminals on the t-stat do the blue, yellow & green wire attached to the control board, attach to on the t-stat....

if our assumption is correct, the white wire on the control board isn't going to be used at the t-stat because it is for the heater

[Dick_B]

Wild guess but could it be wired for two A/C units?
I think for starters I would try to match up the wires at the t/s with the wires in the ceiling fixture ie do a continuity check. Hopefully that would eliminate half of the wires to deal with.

[esty]

thanks for that link bob but that was not any help at all...he used a different thermostat with a different brand ac...i wasn't able to see which wires i have available connect to which terminals on my Honeywell thermostat

[bobndot]

see the last post 'smkettner' for a link with pics to control heat and a/c . Maybe that will help.

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/28838162/srt/pa/pging/1/page/1.cfm

[samhain7]

I started a thread which has what you are looking for.
I'll see if I can find it.