Heater/furnace problem

First trip out this season and I can't get the furnace to turn on. Fan works but no heat.
Propane tanks are full. Turned on the oven/stovetop which is last in line and have flames,
Refrigerator is before range and it works off of propane. Turned off the tank and then opened valve slowly but no change then switched tanks and still no heat.
Don't know what to do next. Any ideas would be helpful as we are in Montana and a little cold here.

Hi skywatcher65,

If the blower runs for 25-30 seconds after the thermostat calls for heat, and you have good propane flow, you've narrowed things down a lot.

First, make sure nothing is blocking either the air return, or the heat vents. Reduced air flow can cause the blower to not get up to speed, which would keep ignition from firing.

Check the test indicator for the battery (on the holding tank monitor). If you have less than 3 lights out of 4, it could be a low voltage problem. You can also check voltage on the Auto-Levelup panel if you have that feature. If below 12.0V, you may have trouble.

Check the furnace intake and exhaust pipes on the exterior wall for leaves or grass or other debris.

If possible, have someone else operate the thermostat to start the blower while you stand next to the furnace to listen for the gas valve opening and an ignition attempt.

If no ignition attempt is made, the most likely cause is a defective control board on the furnace. It could also be the sail switch or a blower problem. But my guess would be the board.

It's possible to replace it yourself, but is not an easy repair. Most people call in a mobile tech. If you do, I would ask him to bring a board with him to avoid a 2nd trip and a 2nd trip charge. If you're staying in a campground, the office may have the contact info for mobile techs.

You can also buy a board yourself from Amazon for about $85. Here's a link.

I have checked and I have a full battery indicator and I have no blocked vents in the RV and the intake and output vents on the outside at the heater are clear with no obstructions.
My rig is a 2019 so how long should the circuit board last? I am in Montana travelling through so can't order anything from Amazon right now. 44 degrees here this morning and a big chilly inside here but have the fireplace in to try and take the chill of.
Steven

How long should the board last? 10 years? 15 years?

Although the trailer has a 1 year warranty, some appliances may have longer warranties. I think a Suburban Furnace now has a 2 year warranty.

You can likely use any repair shop that's willing to submit a warranty claim directly to Air Excel, the furnace manufacturer.

Here's some info.

Had someone come out to check out the furnace. Turns out it wasn't the control board but was the gas valve. Problem is no one in this area has one and we would be home by the time they could get one in. Thank you for all the ideas.
Steven

Took my RV in to have the heater fixed and they replaced the gas valve but also found a damaged wire under the heater. Any idea what it is for?
See picture.


thank you,
Steven

skywatcher65 said:

Took my RV in to have the heater fixed and they replaced the gas valve but also found a damaged wire under the heater. Any idea what it is for?
See picture.


thank you,
Steven

Click to expand...

It looks like it might be the wire to the High Limit (overtemperature) switch. It's at the top of the diagram, to the left of the sail switch.


If that wire opens, the blower will run for about 25 seconds but the furnace won't fire the gas valve or ignition.

Any idea what could have damaged the wire? First time ever to have a problem with the heater so never has been pulled out since we bout the rig new.
Thank you,
Steven

Mice?