Igniter problem on Gas Furnace

Discussion in 'HVAC' started by br8thw8, Jan 13, 2011.

  1. Jan 13, 2011 #1

    br8thw8

    br8thw8

    br8thw8

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    I just recently moved into an old row house (built in the late 1800's) and have an issue with the gas furnace. I was told that the furnace did not work so I had the local gas company come out to do a safety check and light. They don't troubleshoot or repair and they let me know that upfront. So the gas company guy climbs under the house where the furnace is. He immediately sees that the ignitor (spark type, not glow plug) isn't wired up. To my surprise he wires it up and tries to start the furnace. No spark. So he follows the power cord to an outlet and finds that it's barely plugged in. Still no spark. He then tells me that the ignitor control board (Fenwall) is probably bad, and said they are usually cheaply made. But he tries one more thing and unplugs a socket that goes from the ignitor control box to the ignitor, blows it out with some air, plugs it back in and voila! It immediately sparks and the furnace lights. I have heat! For a little while, because later in the day I noticed that the furnace is no longer kicking on. I climb under the house, unplug the furnace from the outlet and start jiggling wires to see if something is loose. Then plug the power cord back in a voila! Sparking and then gas flame. So it goes like this for a while, sometimes the furnace works for a few hours, sometimes for a few days. So I come to find out that it doesn't seem to matter if I unplug the power from the outlet or if I unplug the connector to the ignitor, that fixes the issue and it will immediately start to spark and light. I tried shutting off the circuit breaker to see if that would work, and make things easier than climbing under the house every time I want to relight the furnace, but that never works! This is a puzzling problem, why unplugging the power cord works but not tripping the breaker. I don't think the problem is the control board because unplugging and plugging the connector that goes to the ignitor fixes the issue too. I could be wrong and this why I'm asking for any help or ideas. Thx!
     
  2. Jan 13, 2011 #2

    paul52446m

    paul52446m

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    I just recently moved into an old row house (built in the late 1800's) and have an issue with the gas furnace. I was told that the furnace did not work so I had the local gas company come out to do a safety check and light. They don't troubleshoot or repair and they let me know that upfront. So the gas company guy climbs under the house where the furnace is. He immediately sees that the ignitor (spark type, not glow plug) isn't wired up. To my surprise he wires it up and tries to start the furnace. No spark. So he follows the power cord to an outlet and finds that it's barely plugged in. Still no spark. He then tells me that the ignitor control board (Fenwall) is probably bad, and said they are usually cheaply made. But he tries one more thing and unplugs a socket that goes from the ignitor control box to the ignitor, blows it out with some air, plugs it back in and voila! It immediately sparks and the furnace lights. I have heat! For a little while, because later in the day I noticed that the furnace is no longer kicking on. I climb under the house, unplug the furnace from the outlet and start jiggling wires to see if something is loose. Then plug the power cord back in a voila! Sparking and then gas flame. So it goes like this for a while, sometimes the furnace works for a few hours, sometimes for a few days. So I come to find out that it doesn't seem to matter if I unplug the power from the outlet or if I unplug the connector to the ignitor, that fixes the issue and it will immediately start to spark and light. I tried shutting off the circuit breaker to see if that would work, and make things easier than climbing under the house every time I want to relight the furnace, but that never works! This is a puzzling problem, why unplugging the power cord works but not tripping the breaker. I don't think the problem is the control board because unplugging and plugging the connector that goes to the ignitor fixes the issue too. I could be wrong and this why I'm asking for any help or ideas. Thx!
    --- There is no difference between on plugging it in the crawl space and turning the breaker off and on. I don't know is you hitting the wrong breaker or what. When you turn off the power you should wait 5 min. before turning back on.
    The unit must be going off on safety. That igniter assembly has is a sparker and a flame rod. That that igniter out and clean it real good with some fine sand paper.
    It gets a coating on it from the gas , so even if it does not look dirty, clean it.
    Make sure all the wires are tight.
    Try this first and see what happens. Later Paul
     
  3. Jan 14, 2011 #3

    br8thw8

    br8thw8

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    I'm sure I'm tripping the correct breaker
     
    Last edited: Jan 14, 2011
  4. Jan 14, 2011 #4

    br8thw8

    br8thw8

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    I'm sure I'm tripping the correct breaker since it powers a standard 2 plug outlet and I have a light plugged into it and I see it go off when I trip the breaker. But no, I have not waited five minutes before turning the power back on at the breaker. I'll try that. But then I don't wait five minutes when I unplug and plug in the power cord of the furnace to the outlet either, which always works. To me it's very curious. And I'll try cleaning the tip of the ignitor. Thanks for the tip.
     
  5. Jan 14, 2011 #5

    paul52446m

    paul52446m

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    Don't just clean the tips sand all of the metal.
    Is this plug in a grounded one theses electronic boards need to be on a grounded circuit. Later paul
     
  6. Jan 14, 2011 #6

    br8thw8

    br8thw8

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    Gotcha, will sand all of the metal. I'll try to post some pics too. I'm not sure what the model number is off the plate on the ignitor control box. I've Googled all the numbers with no match. And it's seems like most of these control boxes are like $250, is that high?
     
  7. Jan 14, 2011 #7

    paul52446m

    paul52446m

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    I have no idea what the price would be. The last Finwell i used was many years ago on
    lennox roof top units. 20 years ago they cost me $65.00.
    You can send pic. to me at paulm989@hotmail.com
     
  8. Jan 15, 2011 #8

    joecaption

    joecaption

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    I think I would replace he outlet it's self and also the male plug on the cord. Many times they get corroded just from being under the house.
     

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