Help with furnace

[whacka_moley]

Hello to all.

I was hoping that someone can help me with my furnace trouble. I have. 1996 Terry Travel Trailer and the heat is not working. Based on what I've read online already, I can say that the blower part is not coming on and so I think there is a problem either with the analog thermostat, somewhere between the thermostat and the blower, or maybe the blower itself.

We are thinking about replacing the thermostat to start, but I would like to know if we can use one of the digital Honeywell thermostats from Wal-Mart, and if we did how can I make sure that it is compatible? Any help would be greatly appreciated as its getting pretty cold and I would like to get some heat going. Thanks!

[whacka_moley]

We went ahead and got a new thermostat at Wal-Mart. Based on my research, I looked for one that required batteries. It is a Honeywell RTH111B. It works! I can even set the temp that I want on the LCD screen! It turned on, got to 70, and turned off! We will see if it kicks back on here in awhile. Thank you for your help. I will return if there are any problems.

[enblethen]

Identify the two wires coming from the furnace.
Connect them to the thermostat. (What make and model did you buy?)
Extra wire should go to a relay in the AC unit. It should go to the cold side of the thermostat. This is the wire that goes to the relay in the furnace.
Please post make and model of the thermostat that you installed.
Did you write down where you took the wires off the old thermostat? Take a picture?

[whacka_moley]

Sorry, I got a little abrupt there. He says he checked all of that and still nothing. Now I'm taking the thermostat back to the store.

[whacka_moley]

Okay. So what do I do? What sort of thermostat do I need? Or what do I have to fix? Why didn't the one that I bought work?

[enblethen]

Third wire could be an interlock to prevent AC from coming on when furnace is on.
Locate the two wires in the furnace. See if they are either marked or color coded.
Third wire may need to get connected to the cold side of the thermostat. Identify the one that has 12 volts. the other wire should be cold side.

[whacka_moley]

Sorry that I haven't responded to this topic recently.

We did connect the two wires and the blower/heat does come on! We tried a new thermostat, but it doesn't work. There is a third wire that when hooked up to the new thermostat turns the AC unit on top of the trailer on, but there is a separate box to control the AC and such and then a thermostat to turn the furnace on so we are really confused.

[enblethen]

Start by checking to make sure there is 12 volts DC to the furnace.
The small Atwood mechanical thermostats can be troublesome.
Remove cover on the thermostat. Locate the two wires, connect them together, the furnace fan should start immediately. Run for a short period of time, then the burner should kick in. Separate the wires and the burner should stop, the furnace should go into cool down and shut off.
If the fan doesn't start, then there is a good chance no power to furnace, or the fan relay is not operating.
Test thermostat as indicated for quicker diagnosis.

[whacka_moley]

Yes the furnace worked last winter. Also, the heat is separate from the cool. When you say outside cover what do you mean?

[newman_fulltime]

so the therm is just for the heat?Has it worked before?
Did you look behind the outside cover to see the furnace is on

[whacka_moley]

Well. The AC control next to the thermostat is a Coleman. The only thing on the thermostat cover is Atwood.

[newman_fulltime]

is your thermastat a coleman or durotherm

[powderman426]

To test the system, you can just connect the thermostat leads to eliminate it as the problem. Most likely the problem lies elsewhere.