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bbarnesy's avatar
bbarnesy
Explorer
Sep 12, 2025

Suburban NT-20seq furnace will not light at all.

Fan and motor seems to be working fine, I have good spark at the igniter. Furnace will cycle 3 times than lockout. I hear a click from the gas valve when igniter starts but no gas/flame. Exhaust is clear, as is nozzle on end of gas line. I smell no gas at the exhaust when it is trying to light. I also replaced the board as I was told it was common problem, still no flame. Next step is gas valve as I am at a loss for what the problem will be. I’ll be close to half way there to a new furnace with the purchase of the board and valve. Any ideas would be appreciated.

 

6 Replies

  • how old is the furnace?   I had a similar problem with mine when I first got it and it turned out to be bugs in the combustion chamber and the exhaust. not to say it is your issue but its worth a check.  I pulled the igniter and burner, used a tiny vacuum attachment for computers to clean that side, and I blew compressed air from the outside through the setup, and did this several times until no more evidence of bugs showed up. 

    • bbarnesy's avatar
      bbarnesy
      Explorer

      Bought the camper new in 2019. So 6 years old. I have taken it all apart and have not seen any evidence of bugs. Will try actually blowing it out. Thinking of replacing gas valve next.

      • StirCrazy's avatar
        StirCrazy
        Moderator

        ya, if you can't smell gas outside at the exhaust, that's a good place to start looking, does the igniter fire when you try to start it? 

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