Furnace won't light

N

natjwest

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What's the troubleshooting procedure for a furnace that won't light? In the two weeks I've owned the camper, it fired once, but not since. I have propane (stove and fridge work), plenty of battery power, fan turns. I don't think I hear the tick-whoosh sound. I remember reading something about a reset? But now I can't find it.
 
What model furnace does yours have?

I went a few rounds with my furnace and have now had the entire furnace out 2x and replaced way too many parts... But it works awesome now!!!
 
It's the original furnace from 1991, but I can't see "Atwood" or "Suburban" on it anywhere. There is what appears to be a lighter module on top called "HydroFlame". I secretly want it to be broken so I can reclaim that space and use a catalytic heater.
 
http://bryantrv.com/docs2/docs/hflamefurn04.pdf

http://www.fourwh.com/atwoodfurnaceinstructions.pdf

Atwood Hydroflame. Much information at the above links
 
It should be an Atwood Hydro Flame - Probably a 8516-II - at least that is what my '93 has.

If you need parts all the 8500 series use very similar parts. I was able to walk into my local RV place and get an ignitor and circuit board off the shelf.

The first thing I would do is have the circuit board checked by an RV place. I had mine checked at Curtis Trailer in Hillsboro, but any large place should have the test machine, they didn't charge me anything and it only took 2 minutes. You can pop it out of the furnace in just a few minutes. It is only held in by a wing nut. No need to take the entire furnace out or take the camper to the RV place.

I ended up needing a new board and went with a Dinosaur brand board made right here in our own Lincoln City. Plugged it in, and the furnace took off like a champ!!

If you open the outside door it 'should' have the instructions, model info and circuit layout on the inside.

Good luck!

If you need an extra ignitor, I'm pretty sure I have a spare that works....
 
Perhaps a dumb question but why is it specified the thermostat be at it's lowest setting on start up? If it's warmer than say 50 degrees which I think is the lowest setting nothing should happen even if everything works, correct? I'm having the same issue, fan blows but no ignition. I'm going to start with getting the board tested as indicated above. Mine is an Atwood 8516-IV. It appears the combustion area is sealed for the lack of a better word. If it were clogged with debris not sure how I'd see it or access it?
 
I was having the same trouble with mine. I would turn on the thermostat and the fan would kick on but I never got the click, click, click from the ignighter. The fan would cycle three times and each time the burner would not light. I thought for sure the circuit board got damaged from my last trip with the camper it was really dusty where we were and every part of the camper was coated with it. I gave up and took it in to a repair shop. It ended up being a bad thermostat.
What's silly is I ruled out the thermostat because the fan would kick on. I thought it was fine.
Lesson learned...start with the thermostat. ;)
snow
 
I was having the same trouble with mine. I would turn on the thermostat and the fan would kick on but I never got the click, click, click from the ignighter. The fan would cycle three times and each time the burner would not light. I thought for sure the circuit board got damaged from my last trip with the camper it was really dusty where we were and every part of the camper was coated with it. I gave up and took it in to a repair shop. It ended up being a bad thermostat.
What's silly is I ruled out the thermostat because the fan would kick on. I thought it was fine.
Lesson learned...start with the thermostat. ;)
snow


FWIW: My furnace does this once in a while, but it only does this when the battery charge is relatively low...like there's not quite enough juice to do the sparking -- and yet there's enough to run the fan (but I can tell from the sound that the fan is running slower than normal).
 
Perhaps a dumb question but why is it specified the thermostat be at it's lowest setting on start up? If it's warmer than say 50 degrees which I think is the lowest setting nothing should happen even if everything works, correct? I'm having the same issue, fan blows but no ignition. I'm going to start with getting the board tested as indicated above. Mine is an Atwood 8516-IV. It appears the combustion area is sealed for the lack of a better word. If it were clogged with debris not sure how I'd see it or access it?


I say it shouldn't matter where you set it-- the thermostat sends a signal as a relay (12v on or off) and not a rheostat/potentiometer (variable resistance based on the setting) to the furnace. If you didn't care about temp settings you could run the furnace with an on/off switch.
 
FWIW: My furnace does this once in a while, but it only does this when the battery charge is relatively low...like there's not quite enough juice to do the sparking -- and yet there's enough to run the fan (but I can tell from the sound that the fan is running slower than normal).


When it first started I thought the same thing. So when I got a chance I plugged it into shore power and it made no difference. The circuit board led was no help, it just stayed on solid. No flashes, blinks, or S.O.S. signals to be helpful.

Well I do have a spare board now. :D It's always good to have a spare tucked away just in case. :oops:
 
I say it shouldn't matter where you set it-- the thermostat sends a signal as a relay (12v on or off) and not a rheostat/potentiometer (variable resistance based on the setting) to the furnace. If you didn't care about temp settings you could run the furnace with an on/off switch.


Thanks, that makes sense, I had the board tested today and it was fine. Bought a ignitor, will put that in and see if that's the issue. I'm getting ready for hunting season and can't wait.
 
I installed the ignitor, still no heat. I read that I should hear it clicking but can't seem to. Maybe it's me. I suppose if it's has spark if I so assume after testing the board and installing the ingitor then I'll look at gas next. I think I'm missing the old pilot light furnaces already.
 
have you tried the reset switch ?


-----------------------------------------------


I installed the ignitor, still no heat. I read that I should hear it clicking but can't seem to. Maybe it's me. I suppose if it's has spark if I so assume after testing the board and installing the ingitor then I'll look at gas next. I think I'm missing the old pilot light furnaces already.
 
have you tried the reset switch ?


-----------------------------------------------


Well, this is a bit embarrasing :unsure: but perhaps someone will read this and and prevent their own Duh moment. The battery cables were reversed, corrected the polarity and bang she fired up. I was sitting on the couch watching football and comtemplating taking it in to a shop and it hit me to check the obvious.
 
Well, this is a bit embarrasing :unsure: but perhaps someone will read this and and prevent their own Duh moment. The battery cables were reversed, corrected the polarity and bang she fired up. I was sitting on the couch watching football and comtemplating taking it in to a shop and it hit me to check the obvious.


That makes you an official member in good standing of this forum!
 
The reset on mine is in the furnace on the outside of the fan shroud -- in the picture below it is the black square with the little white button on top in the right part of the picture...

dinosaur.JPG
 
The reset on mine is in the furnace on the outside of the fan shroud -- in the picture below it is the black square with the little white button on top in the right part of the picture...
Yeah, I thought so. That button does nothing for me. Thanks for the picture.
 
Yeah, I thought so. That button does nothing for me. Thanks for the picture.


If the button is 'soft' it hasn't been tripped and will feel like it does nothing.
 
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