# Furnace exchaust makes thundering like noise



## Adam (Mar 10, 2003)

My furnace makes a "thundering" noise out the exhaust port intermittently, sound like when someone pulls up next to you with one of those super bases in their car! It does it for a few seconds and then the noise disappears again and may not happen for a couple of days. I feel its got to have something to do with the mixture but not sure where to start. Any ideas?


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## Gary B (Mar 10, 2003)

Furnace exchaust makes thundering like noise

Hi Adam, don't think its the mixture, but would be supisious of the ignitor, the ignitor electrodes may not be properly adjusted, and maybe sparking in the wrong area and not igniting the LP gas right off letting the burner area fill with LP then it ignites with a bang. On second thought check the air intake tube and area it could be drawing in exhaust thus killing the flame temperarily then reigniting with a bang, guess that would be mixture. Good luck.


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## ARCHER (Mar 11, 2003)

Furnace exchaust makes thundering like noise

Might also be the intake/exhaust tubes could have critters/spider webs, etc., in them.  Check it out.


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## Adam (Mar 13, 2003)

Furnace exchaust makes thundering like noise

  Thanks for the replies Gary and Archer, I am looking through the furnace owners book right now so I can figure out how to access the furnace burner area. I will post what I find as an answer.


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## Kirk (Mar 17, 2003)

Furnace exchaust makes thundering like noise

Since you have not yet returned with a solution, I'll offer another thought. Could the problem be something loose that is at times vibrating?


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## Adam (Mar 19, 2003)

Furnace exchaust makes thundering like noise

  Thanks for the thought Kirk, but as of yet I have not figured out how to remove the unit from my trailer to inspect. I am planning to do it this weekend. I probably would feel better taking it to a dealer, but the problem is to intermitten, and at $60. per hour it would add up fast!


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## Butch (Mar 19, 2003)

Furnace exchaust makes thundering like noise

If the furnacd problem is on that 2003 Artic Fox, is it not under warranty???  If so why would you worry about the $60 per...


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## Adam (Mar 19, 2003)

Furnace exchaust makes thundering like noise

Hi butch, the dealer, like the factory said by desciption it sounds like a insect/web has gotten into the burner area which would not be covered. So I thought I would check for that first myself before taking it in!


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## Adam (Mar 24, 2003)

Furnace exchaust makes thundering like noise

Well I finally figured out how that darn furnace comes out, with the aid of the owners guide I was able to disassemble the unit and inspect/clean the intake and fuel supply orifice for any foreign items. Didn't find anything. With the outer box off I rehooked the unit to the gas supply and fired it up so I could watch it operate. You talk about a hot blast of air in your face!! I put everything back in and decided if it continues to act up this weekend I will run it back to Thunder RV(the selling dealer) for them to figure out as I have gone as far as I can myself. Thanks for the input from everyone, if it acts up and they figure it out I will post the answer.


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## lookn-ahead (Mar 29, 2003)

Furnace exchaust makes thundering like noise

Friend has a Thor with the same problem.  Sounded like a rumbling jet engine.  I was able to stop it by cutting down on the amount of air at the mixture tube.  There is a small screw and allows the pipe to be adjusted.  Use the smallest amount of adjustment that quiets the problem.


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