Community Forums

harmonybrew · 02-05-2019, 01:49 PM

The furnace is not working on my 99 Bounder, 34V. I took the cover off, found a nest of some sort, destroyed it and vacuumed it out. You can see a before and after picture below. It didn't help. There may be another nest further back where I can't see it. Or maybe the ignitor probe is corroded, I had this happen with the water heater a few times. Each time I cleaned it up with some sand paper....whoosh, away it went again.

Here's where I am at.

I turn on the furnace at the thermostat. The blower kicks on for about 10 seconds to clear out the chamber then I get a click and the smell of gas. About fifteen seconds later, the same thing.....three times. But, no fire and no hot air. It had been working.

I can tell that I am going to have to remove the darn thing. But before I do that, I was hoping from some advice from someone with a little experience. Without this advice (if left to my own devices), I would turn off the gas at the tank, unscrew the line where it comes into the furnace (see pic), pull out everything I could, work on it, put it back in, screw the propane line back on, turn the gas back on, and...........see if I blow myself up.

Any advice would be great. I will not be calling a professional. I can't afford it and I like to do things myself. That being said, for those who would have suggested that, if you can give me some advice on how I can educate myself as best as possible before digging in, I would be happy to do the research.

Thanks folks, and happy RVing!

Marcus

PS. I have included other pictures that may not be useful, but I guess it never hurts.

W4KMA · 02-05-2019, 03:55 PM

In your center picture is, I believe, the sail switch. It is normally open but closes when the fan moves air. If it is defective, you won't get a spark to ignite the gas. You can bypass it by connecting its two wires together.

Here's a list that I saved from someone's post on the operation of most RV heaters. There's lots of on line help on the subject.

Thermostat calls for heat.
Thermostat relay or time delay relay is energized and allows power to the blower.
Blower motor runs up to speed.
Sail switch closes at 75% of rated blower speed.
Power goes through the limit switch to the ignition control board.
The control board begins trial for ignition, opening gas valve and initiating ignition spark.
Burner ignites.
Thermostat reaches setting and opens.
Burner shuts down.
Fan runs briefly to cool furnace.

Good luck, hope it's a cheap fix.

Ed

Old-Biscuit · 02-05-2019, 04:28 PM

If sail switch didn't close you would NOT get ANY DC to circuit bd for GAS Valve or Igniter....
BUT you ARE cause you hear it CLICK and smell GAS

Sail Switch is NOT you issue

A dirty burner and/or igniter IS the problem
Need to pull burner/igniter and clean ....

https://techsupport.pdxrvwholesale.c...uburban-sf-42/

Waiter21 · 02-05-2019, 06:40 PM

^^ YUP What he said.. You're getting gas, but no ignition.

my money is on a dirty ignition probe thats shorting out or not allowing the spark to jump.

harmonybrew · 02-06-2019, 04:13 PM

I am about to hit the road for the next week, so I won't be able to get the job done until I land in San Antonio. But, after that I will take the heater out, clean the burn chamber and ignitor and see what happens. I will post the results here and include a picture or two. I hope this helps other people as well.

Marcus