Gas furnace won't turn on :(

[Walkerfam7]

Hello all! This is my first post and I promise I will do an introduction if there is an are to do that, but I have to ask for some help first. My family is new to RVing no we will be on here a lot...lol.
So, about three weeks ago we bought our first motorhome, a beautiful 40' 1995 Fortravel U300. It has lived its life in the nice dry, warm south and we have brought it home to cold, damp Michigan 😕 So far, we haven't had any problems, really, but last night the front end propane furnace went out. It just won't turn on. I can hear the click of the connection happening in the thermostat and I have changed the batteries and tried a reset on that, so I'm pretty certain it isn't the thermostat. But, after the click of the thermostat, nothing. Not a sound. So, I have checked the fuse (it looks normal), checked that the motor switch is in the on position and pressed the rest button on the motor. Anyone else have any ideas what I can check?

Thanks!

[bud01234]

I may have missed it, but does the fan come on but there's no heat?

If so, then it's probably a circuit board or sail switch problem (neither one is really expensive and fairly easy to DIY.) Also, could be a bad igniter but you can usually hear the igniter snapping if operating.

If no fan blowing then, as was mentioned earlier, the burner won't light without the fan. Then it's a fuse or possibly fan motor problem and trying to light the LP.

[Paradox123]

Some years back I had an issue with my furnace not igniting. Turned out it was low propane pressure. I changed the propane regulator and the problem was solved.

[Old-Biscuit]

Per the link to previous owners issue you have a 1994 vintage furnace (8516 III) so should have a 'timed delay relay' (changed in 2001 to on the circuit board)
Previous owner changed board to a Dinosaur Board......should be a UIB-S Dino Board and will have a 'diagnostic' light on it
Green LED on steady.OK
No light---then Limit Switch, Sail Switch or the 5A Fuse on borad needs checked

Should have 12V DC power to that ON/OFF-circuit breaker that is on frame.
DC power is there all the time.
Then when t-stat calls for heat (contacts close) DC is sent to timed delay relay which allows the DC at the ON/OFF-CB to go to fan motor

On/OFF-CB should not be loose...should be strong distinctive resistance when pushed/reset


So either no DC to the on/off-cb (or going thru it when called for)
OR timed delay relay is bad

[ORbiker]

Here is a SERVICE MANUAL .

Look at pg 16 and 23 to start if the motor will not even start.

[easttexan]

I had one quit on our way to Alaska last summer and it was sail switch. It looked like an easy fix, but you definitly have to know how to get to it.

[Walkerfam7]

My husband is going to pick up a multimeter on his way home from work and we will check to see if something isn't getting power.

[Walkerfam7]

enblethen wrote:
Some furnaces have a circuit breaker mounted to the fan housing. They have a red or white reset button.

Yes, I have tried pressing this button. It isa very loose button and doesn't really feel like it's engaging anything, but what do I know....lol.

[enblethen]

Does the fan run?
If it does not, you need to check for power to the furnace, the fan circuit breaker and the thermostat.
If it does then depending on model, it could be sail switch, ECO or circuit board.

[Walkerfam7]

I don't think there is a leak in the compartment, but there is a vent where heat is release and that is where the water got in.

I did read the link hat Old Buscuit sent. That's why I said he gave good info. I followed the suggestions and it didn't help.

Here is another thread to explain the recent replacement of the control board. Maybe this thread that he posted can help. I completely trust the previous owner. He was not at all trying to do anything suspicious. I think though the original problem may not have been completely fixed by he dinosaur board and I may need to look at another option or have a professional check it out.

https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/28577367/print/true.cfm

[enblethen]

Some furnaces have a circuit breaker mounted to the fan housing. They have a red or white reset button.

[Sam_Spade]

the bear II wrote:

Thermo coupler may have failed....this is common. Here's some info http://www.rvforum.net/SMF_forum/index.php?topic=22178.0

Does a unit without a pilot light still have a thermocouple ??

More likely that the electronic ignitor has failed.

BUT....the recent replacement of the control board is a bit suspicioius.

Professional assistance might be required.

[Joe417]

It will not hurt to try a correct size fuse if you aren't sure the current fuse is bad. If you do have a blown fuse you would stand the chance of blowing another. To prevent that you can try the furnace fuse in another slot that you know is working. That way you don't blow another.

All situations are different, but a bit of water in the floor under the furnace doesn't usually cause a problem. But it does sound like you have a bit of a leak in that area you'll need to seal up.

Read the link Old Biscuit sent, there may be something in there about that particular model that will help find the issue.

[USAFBILL]

Do not switch fuses around unless you are certain the fuse is rated the same as the fuse your wanting to swap out...good luck

[Walkerfam7]

Oh...and another thing that might be important to mention....we washed the motorhome for the first time a few days ago because it had gotten so filthy with salt and road grit. Well, when we did open the furnace compartment today to have a look, the floor of the compartment was wet, so we must have gotten water in there when we washed (we didn't really think about the fact that there could be areas we would need to be careful when rinsing with the hose). Could that have caused a problem?