Honeywell RTH3100C Thermostat wiring

[jadinolfi]

I have a 2000 Montana 3555 5th wheel and replaced the air conditioner with a Duo-Therm 15000 BTU Heat Pump. The analog thermostat is not very accurate so I want to install a digital thermostat. The Honeywell RTH3100C is made for a heat pump setup so I purchased one. This is after I had purchased and returned a Duo-Therm Comfort Control which needs wires that I do not have to work. My question is that I am unable to find what wires from the Duo-Therm go to the Honeywell. I have checked Honeywell's site and dozens of forums to find a wiring diagram with no results. Does anyone have or know where to get the information as to what wires go where on the Honeywell. I know where the Duo-Therm wires come from and what they control.
Thanks

[Tinman1947]

Here is the link for the installation instructions. http://customer.honeywell.com/techli.../69-1889EF.pdf Just copy into the address bar and it should open to the install instructions. If you have the wiring scheme for the existing thermostat perhaps I can help.

[Luv2go]

jadinolfi:

Welcome to iRV2.com!

I'm not quite sure which DuoTherm HP you purchased, there are a couple, only one type of which will work with an analog thermostat. It may also work with the normal house thermostat like the Honeywell. Installation instructions for it are here:

http://bryantrv.com/docs2/docs/operating/bairducted.pdf

As you found out, the other Duo Therm HP's will only work with the Comfort Controls and will require running a 4-wire cable from the unit to the thermostat.

Several people have used house thermostats on RV air conditioners but not heat pumps. Here is the closest I found, it has the same color wires as the manual says it should on P16:

RV Digital Thermostat Upgrade | ModMyRV

It looks like the Violet wire on the HP would be for the reversing valve, which would hook to the O terminal on the thermostat. So the wiring would look like this:

Color on HP diagram - thermostat connection
Violet - O
Yellow - Y
Orange - G - (this will run the low fan speed, if you want high also, hook the blue thru a switch as in the link above)
White - E and Aux (if a furnace is connected to the HP)
Black - R

Please note these are my educated guesses, I cannot guarantee this will work, but should not harm anything if hooked up wrong. If you get heat instead of cool you should move the Violet wire to the B connection on the thermostat.

If the thermostat requires 24VAC to run the relays it will not work. You may be able to use the +12V (Red) wire, but you have a much better chance of breaking the thermostat or Heat Pump if you connect it wrong, and I do not know which terminal on the thermostat to try.

Good luck!
Stewart