Replacing thermostat for gas furnace only

Congratulations! You will be happy with the new thermostat. You will probably find that the AAA batteries will last you quite a while. We get a whole Pennsylvania camping season out of a pair with usable power left. Now do yourself a favor and throw that cheapest thermostat in the world into the trash. Well, maybe keep it for emergency backup or just twist the wires together when you need.

Thanks guys......W is White wire and R for Red wire (according to Honeywell tech) so I tried it and it worked!! Simple fix and now need to keep supply of AAA batteries just in case they drain down (no battery/no heat!!).

I have the RTH111 as well now. Use R and W and leave the jumper in like DrewE said. Not sure about red and white wires. With ours, it is two blue wires to the thermostat, where the blue wire is connected and disconnected by the thermostat. With the two blues it doesn't matter which goes where

Easy to check if you have the right two wires- just connect the red and white ends to see if the furnace then comes on.

Those codes are more or less standard, although inscrutable to non-HVAC professionals. Often I think the colors of the wires correspond to the letters.

R is common (Rc is for cooling, Rh for heating, and if both exist there's often a jumper connecting them together).
W is heat control
Y is cooling control
G is the fan control

I don't recall offhand what B and O are generally for; one's probably the 24VAC power from the transformer, one might be for a heat pump or something like that. At any rate, you need to use W and R for the furnace operation and ignore the others. It oughtn't matter in this particular case which one goes to which connection, but red to R and white to W seems to me to be more aesthetically correct than vice-versa.

Ok, got a Honeywell RTH111 non-programmable termostat.....question: It has 8-wire pins on back labeled "B,O,G,Y,W, R, Rc" and don't know which to hookup the red or white wires coming from my old thermostat. Anyone know which to use? As usual, the diagrams on instructions are almost impossible to understand. Trial and error should give me the answer, but thought I'd ask beforehand. Thanks!

While looking at the igniter. Check the connection on furnace control board. I needed to use some contact cleaner on the board where a wire connector attaches to the board.

Well, hoping for the best! Mine sees alot of beach use and think the spring in the old thermostat has rusted up some because when I move it back and forth a few times, it normally starts working ok again. But, if not, will certainly look at the igniter. Only cost $22 for the cheapo new unit from Lowe's. Thanks!

Had those symptoms, got the digital thermostat, furnace still does that. It is more to do with the burner and ignition.

After some efforts there, it mostly cycles ok, but once in a while just blows cold air and you have to shut it off, wait till fan stops, turn it on and after fan starts wait for the boom when it comes on properly.

It has nothing to do with the thermostat in our case. Might in your case, but don't be surprised if that doesn't solve everything.

Will do..........thanks as always!!

naturist wrote:
Go to Lowe’s or Home Depot and buy one of the cheaper thermostats for home use. Nobody needs 7- day programmable internet access for a camper. The cheapest home thermostat just needs to close the circuit when the set temperature is reached and open the circuit again a degree or two warmer.

I agree, a digital non-programmable is all you need.