Can't light Coleman furnace

Discussion in 'Shop Talk' started by farmergirl, Jan 17, 2007.

  1. farmergirl

    farmergirl Well-Known Member Supporter

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    So we got clever a few months ago and decided to turn off the pilot for our central heat...and now we have a freak icestorm and can't get the thing lit again. :Bawling:

    Mobile home purchased in 1985. Instructions advise we should "flip up pilot window, flip dial from off to pilot, depress dial while lighting pilot." This all sounds straightforward...but the pilot is really deep in there and there is a breeze inside the furnace! We simply can't get a match close enough to light the pilot without it being blown out. Same issue with a long-nosed lighter.

    Any thoughts?
     
  2. PyroDon

    PyroDon Well-Known Member

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    sounds like the thermo coupler is bad (about a $4 piece) it connects to the valve by a very small copper line .
    Will the pilot lite at allven when held in the lite position on the valve. You often have to push down ot lite the pilot or theres a spring loaded position.
     

  3. farmergirl

    farmergirl Well-Known Member Supporter

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    No action at all when I hold it down...I've given it about two minutes with no result. I'l look into replacing the thermal coupling.
     
  4. PyroDon

    PyroDon Well-Known Member

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    you might also try using a cotton ball on a heavey wire soaked with alcohol it will burn quite a while and the extra time is sometimes needed
     
  5. hunter63

    hunter63 Well-Known Member

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    You need to get a long wire (coat hanger) wrap the end with elect tape, light it, let it get going good, then depress the button, stick it in.

    The breeze should make the fire on the end of the wire burn more and not blow it out.
    (P.S. I use cork/tar insulation, but it not something everybody has laying around.)

    Hold down till the pilot lights and count to 60 slow, then hold it down some more.

    Need to get the thermocouple heated as it will generate about 30Mv electricity to keep the pilot valve open.
    Then let it back up, if it stays burning, then turn the valve knob to "ON"
    If it doesn't stay lit, take a 3/8 whench and loosen the little "tube" nut on the valve, then tighten it again. Some times it get moisture under it and doesn't make a good connection.
    Try it again, if it still doesn't stay lite, need a new thermocouple.


    Found a lighter at Menards that has a 18" end on it, for lighting water heaters, 'bout $20, but I use mine every day on my job
     
  6. Bearfootfarm

    Bearfootfarm Hello, hello....is there anybody in there.....? Supporter

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    This may sound foolish but did you turn the gas back on? The thermocouple doesnt have anything to do with LIGHTING the pilot. It only KEEPS it lit
     
  7. PyroDon

    PyroDon Well-Known Member

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    not a foolish question at all .
    I watched my father and his friend take off and clean injectors and were ready to take off the pump on a diesel tractor , when I asked did ya turn the fuel on ?
    of course we did ! then why is it off now . he had bumped it with his knee .
    :)
    guilty of forgetting to turn the valve on my self in the past
     
  8. farmergirl

    farmergirl Well-Known Member Supporter

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    Well, thanks to everybody for the good suggestions. I knew I could count on you guys! Ended up waiting til it was less windy outside and used a long stick of incense to get it lit. So for the first time in months, we had central heat last night. Woo-hoo! Now here's another question: Why would there be a breeze at all in the chamber where the pilot is? Should I check all the duct work to looks for leaks??
     
  9. hunter63

    hunter63 Well-Known Member

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    Combustion air and duct air are COMPLETY separate, they better be, any way.
    If they aren't, then you have a crack in the heat exchanger, very dangerous. Carbon Monoxide.
    Usually the pilot would only blow out if the blower is running if this was the case.

    Mobile home furnaces do this as the venting is close to the combustion area, not like in a house that has a fairly long run up to the end of the vent. Pretty normal.

    When I gets warmer out, climb up to the roof and check and see if the vent cap is still on and in good shape.
     
  10. liveswithinlogs

    liveswithinlogs Member

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    The breeze is the result of the draft up the flue. Even without the pilot or burners being lit there'll be a bit of a draft, especially if there's a breeze blowing outside. The wind blowing across the top of the flue will create a slight vacuum in the fluepipe, and air will be drawn into the chamber and up the flue as a result of the vacuum. Warmer air inside the house, even if it's just a bit warmer than the air outside, will result in a flue draft as well.