No D.C. Power at thermostat.

hellfirehydra wrote:
Sure. The old thermostat and new thermostat have the wires going to the same components minus not having the gray low speed fan wire.

Blue is the hooked up as a common ground.
Green is hooked up to the high speed fan. 0V DC
Yellow to the compressor. 0V DC
White to the furnace. 0V DC
Red to R & RH. +12V DC

Again, the AC functions normally. The heat function causes the issue with the thermostat heating up.

The furnace functions normally with the white wire attached to the red wire that is hooked up to R & RH.

Ok just figured it out. Blue was not supposed to be connected in addition to white unless I had a heat pump. Blue is a -12v wire and in new thermostat blue is for a heat pump. Disconnected blue and now the AC and furnace both operate properly. It was even a warning in the instructions...oops.

Who knew I should have read the book full of words and pictures more carefully. I was mixing and matching instruction manuals in my head between old thermostat and new.

So I ended up with yellow, green, white, and red hooked up. I capped off blue (-12v) and gray(low speed fan).

Thank you all for the help.

Sure. The old thermostat and new thermostat have the wires going to the same components minus not having the gray low speed fan wire.

Blue is the hooked up as a common ground.
Green is hooked up to the high speed fan. 0V DC
Yellow to the compressor. 0V DC
White to the furnace. 0V DC
Red to R & RH. +12V DC

Again, the AC functions normally. The heat function causes the issue with the thermostat heating up.

The furnace functions normally with the white wire attached to the red wire that is hooked up to R & RH.

OK... But, the conversion isn't necessarily "wire to wire" as some one posted earlier with a link to a "sample conversion". Did you follow this method. Can you outline your wiring both previously (old therm) and new one. My guess would be that you may have "mixed" 12v and 120v wiring requirements.

I have done the conversion from an atwood manual furnace only to a digital thermostat for both furnace and ceiling AC. There was need for some "mods".... hence, the comment. Since your system was heat and AC originally, hopefully, the mods at the unit end were already in place.

added: I re-read your previous posts about checking the voltage at the wires at the thermostat... you said that they were OK... but can you outline what they are / were.

Chris Bryant wrote:
On the old mechanical thermostats, that would be an incorrectly set (or oxidized) anticipator. Not sure what's up with yours.

It definitely has me puzzled. I think I'm going to pick up another thermostat in the morning and see what happens.

The only thing I'm not 100% on is the fact that it is a "residential" thermostat. However, with it operating off of batteries, all of the opening and closing of circuits is ran by the AAA's which means it should work to me?

I mean it definitely works awesome for the air conditioner! Not sure why the furnace would be any different.

On the old mechanical thermostats, that would be an incorrectly set (or oxidized) anticipator. Not sure what's up with yours.

budwich wrote:
back up a bit. Are you trying to wire in a new digital thermostat or is this an existing install? Normally, thermostats are used to switch "control lines". It looks like you are are trying switch wiring that is running your furnace (ie. high current / power).

My analog Coleman T-stat quit working so I am trying to get the Honeywell T-stat working properly. Air cond. compressor, fan, and thermostat are all operating properly while in cooling mode.

Whenever I switch the T-stat to heat, the T-Stat itself gets warm and the furnace never comes on.

I checked to see if the furnace was working by manually jumping the wires. The furnace operates normally with the wires jumped.

back up a bit. Are you trying to wire in a new digital thermostat or is this an existing install? Normally, thermostats are used to switch "control lines". It looks like you are are trying switch wiring that is running your furnace (ie. high current / power).

Coleman AC. There is a jumper between RH and R installed. This is hooked to the red wire from the furnace. W is hooked up to the white wire to the furnace.

Furnace works properly with red and white touching outside the thermostat.

The thermostat circuit board gets hot as soon as I set it to heating mode. Is it possible I got a bad Thermostat or more likely i'm missing something?

I mean I am literally disconnecting the white wire, touching it to the red terminal and the furnace starts right up, but with the white wire in its designated contact, the whole thermostat board heats up when I select heat.

What air do you have, what is hooked to RH and W on the thermostat ?

try this thread Honeywell Thermostat mod mine just runs off its own batteries going on 2 years now still working. lots of you tube videos also you tube