Enable furnace after installing Houghton AC

[lgharis]

I installed a cooling only 13.5k BTU Houghton (Rec-Pro) AC unit last summer. This disabled the thermostat on the wall and therefore the furnace.

I just installed a Dometic heat only thermostat for the furnace. There are 2 small white wires and 2 small red wires in the roof where the AC unit is located. Connect the two white wires and connect the two red wires.

Remove the old wall thermostat. The connections to this thermostat was two blue wires and a white wire. The blue wires are not needed. Connect the white wire to the W terminal of the new furnace thermostat.

There is a red wire in the bundle with the white wire that was not used in the old implementation. Strip the end of the red wire and connect to the R terminal of the new thermostat.

TESTING: You can test that the furnace will start by touching the red and white wire together. THe furnace fan should start(it will shutdown after a few minutes).

Now I just need to wait for cooler weather to perform a full test but this is promising as the furnace was working fine before I installed the Houghton AC.

I like the Houghton AC for two reasons. First of all it is about 10 decibels quieter than the Dometic Penguin unit on the 2017 RPod 178. Secondly, I can change the AC settings with the remote without having to get out of bed. Third, there are ON/OFF timer settings that will turn the AC on and/or off at specified times.

[tonybrownphoto]

hello... saw your post. you saved me a lot of hassle.

I did the same this with my air conditioner upgrade. Did the Dometic heat only thermostat work?

GREAT instructions!

[rlj111727]

My situation is similar to yours, I purchased a 2014 Berkshire 390Bh and the 2 rooftop ac units had been replaced with Houghton disabling my 2 furnaces , so I pulled indoor grilles off the ac units only to find a 2x4 junction box full of capped off wires , if I connect the red and white tstat wires heat functions with no way to regulate temp ... BTW this is the case with both . My existing tstat was a multi zone to control both heat and ac . I'm thinking some type of relay pack was removed with existing rooftop ac's. Is anyone familar with the existing setup from factory ? The only wires on my tstat is a phone plug ... no terminals . Thanks for any help .