Atwood furnace not working

[frankp8285]

our Atwood 8500-IV Series Furnace would not start up. work and then after a trip did not work. Funny thing is, when I turn the Duo Therm Thermostat to “furnace” and slide the temp control up, I hear a “click” coming from the roof Air Conditioner. Any ideas? Could the problem be in the thermostat?

[enblethen]

You could try resetting the thermostat. Remove the cover, there should be a glass fuse. Remove it for 15-20 seconds. Then re-install it. Let the thermostat think for a 10-15 minutes.
The thermostat wires should be next to the 12 volt DC supply wires on the lower left corner of the exterior access.

[frankp8285]

enblethen wrote:
You should be able to see it by removing the inside ceiling cover. Many are about 1 inch cube style relay.
Did you try jumpering the blue wires in the furnace?
Thermostat issues can be hard to identify. What is make and model of the thermostat?

the thermostat is a duo therm by dometic comfort control.
I did not try to jumpering the blue wires because I did not see the blue ones. I will try tomorrow since it is raining here today.

[enblethen]

You should be able to see it by removing the inside ceiling cover. Many are about 1 inch cube style relay.
Did you try jumpering the blue wires in the furnace?
Thermostat issues can be hard to identify. What is make and model of the thermostat?

[frankp8285]

frankp8285 wrote:

enblethen wrote:
Some setups when using a common thermostat have a relay in the AC unit.
I would start by jumpering the thermostat leads in the furnace. There should be a terminal strip with two blue wires. Connect them together. The furnace should start and produce heat in a minute or so. If it does the good chance problem is not in furnace.
Relay, wiring or thermostat issue.

Thank you. Where is the relay that could be defective?

how do I know it is the thermostat

[frankp8285]

enblethen wrote:
Some setups when using a common thermostat have a relay in the AC unit.
I would start by jumpering the thermostat leads in the furnace. There should be a terminal strip with two blue wires. Connect them together. The furnace should start and produce heat in a minute or so. If it does the good chance problem is not in furnace.
Relay, wiring or thermostat issue.

Thank you. Where is the relay that could be defective?

[frankp8285]

darsben wrote:
Service Manual here
Not an answer but a place to start diagnosing your problem

Thank you I will take a look.

[enblethen]

Some setups when using a common thermostat have a relay in the AC unit.
I would start by jumpering the thermostat leads in the furnace. There should be a terminal strip with two blue wires. Connect them together. The furnace should start and produce heat in a minute or so. If it does the good chance problem is not in furnace.
Relay, wiring or thermostat issue.

[darsben]

Service Manual here
Not an answer but a place to start diagnosing your problem