2022 Volante 34RE - Furnance wont turn on

[tcrsurf]

My furnace wont turn on. When I turn on the thermostat, I can hear a click in overhead AC unit but the furnace wont turn on (no blower no nothing) I have checked fuses, reset breaker, propane, etc but nothing worked. Its a domestic system. If I switch the thermostat to AC, AC turns on.

[DavisK]

Welcome to the forum! Try turning on the stove or the gas hot water heater to purge all of the air from the gas lines. It would help to purge the air from the line if you can light something that is further away from the propane tanks than the furnace.

[tcrsurf]

Originally Posted by DavisK

Welcome to the forum! Try turning on the stove or the gas hot water heater to purge all of the air from the gas lines. It would help to purge the air from the line if you can light something that is further away from the propane tanks than the furnace.

Yes, I’ve done all those things. I was thinking it might be the sail switch or the furnace boad but wanted to see if maybe I’m missing something, I don’t have an external access panel so I will have to pull the furnace out from the inside. . Dometic said it may be a board in the ac but I’ve only changed out a sail switch and board on my older trailer furnace never had to mess with the AC.

[dagst1]

Before you pull the furnace out remove the air return and look for the wires to the furnace. There should be 4. Not sure on the color of 2 of them but 2 should be blue on the furnace side of the connection. Those are the thermostat wires. The other 2 are the power + and -. Take a meter and check those 2 for 12 volt. If so then disconnect the 2 blue wires and connect the ones from the furnace together. This is the same as turning on the thermostat. The furnace should turn on. If so the board in the AC control box is probably bad.

If you do not have 12 volt on the 2 +and - wires look at the fuse's again for a blown one. Pull it out even if it looks good and make sure it is making a good connection.

I had a problem and called Dometic and this was the test procedure they gave me for my set up.

[tcrsurf]

Originally Posted by dagst1

Before you pull the furnace out remove the air return and look for the wires to the furnace. There should be 4. Not sure on the color of 2 of them but 2 should be blue on the furnace side of the connection. Those are the thermostat wires. The other 2 are the power + and -. Take a meter and check those 2 for 12 volt. If so then disconnect the 2 blue wires and connect the ones from the furnace together. This is the same as turning on the thermostat. The furnace should turn on. If so the board in the AC control box is probably bad.

If you do not have 12 volt on the 2 +and - wires look at the fuse's again for a blown one. Pull it out even if it looks good and make sure it is making a good connection.

I had a problem and called Dometic and this was the test procedure they gave me for my set up.

Thanks!! I will try it!

[Wingerdinger]

Both Dometic (Atwood) and Suburban have good troubleshooting sections in their service manuals, available on their websites.
One thing that comes to mind is that you said you hear a click in the A/C unit.
I am thinking that you have an auxiliary heating coil in the A/C unit, and you have the thermostat set to run it, and not the gas furnace.

[dagst1]

Our camper has 2 AC's both Dometic and a Suburban furnace. There are control boxes in each AC. The rear control box not only does the rear AC but the furnace as well. Everything is controlled by a Dometic Comfort Control 5 button thermostat. When we turn on the heat and you can hear a slight click from the control box.. A complicated system for a easy task.

[tcrsurf]

Thanks! It’s been storming here so I haven’t been able to test the board. I will do it this weekend.

I have 2 acs and a furnace. 1 ac and furnace are controlled by the dometicthermostat and the other has its own controls. They are all dometic units.

[tcrsurf]

Where would the air return to the furnace be? Is it the overhead ac area or is it actually where the furnace is?

[Wingerdinger]

Originally Posted by tcrsurf

Where would the air return to the furnace be? Is it the overhead ac area or is it actually where the furnace is?

It is right at the furnace. You will usually have some sort of louvers in front of the furnace, that is the air intake, and is the access to the furnace for service.
There is a troubleshooting procedure in the service manual, did you get that?
if you have no blower at all, it's not the sail switch.
The board in the furnace area has an led that flashes trouble codes.
It's in the manual.