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Baffled trying to repair customers Lennox Furnace

Discussion in 'Residential' started by johnroberts, Sep 11, 2017.

  1. johnroberts

    johnroberts New Member

    Messages:
    2
    Hi


    I was wondering if you can help me with an issue I have with a customers Lennox Furnace G40UH-36A-070-14 that utilizes control board 100973-01 0106N046148 1012-969. According to the owner’s manual this model/control board combo uses a mini nitride igniter 75M21 95v. My problem is when I initiate Heat command I never see the igniter glow. Upon turning on the heat cycle at thermostat I see the exhaust blower turn on but nothing else happens. I disconnected the connector that connects the igniter to the control board & did a OHM check & see 278.9 ohms (according to the owner’s manual reading should be 50 to 450 ohms). So igniter appears to pass resistance test. I kept the connector disconnected & initiated heat command again & had ac voltmeter connector to other side of igniter connector & see 110V ac. I see both status LED’s (1 green & 1 red) blinking simultaneously every second or so (I believe this indicates normal operation). I am baffled why the igniter does not glow when 110v ac is sent to it. As a side note I replaced the hose from exhaust blower to pressure switch. I do notice flame sensor has a little carbon on it that I have to clean off. Any help/info you could provide me would be very much appreaciated.


    Thank you & regards


    John
     
  2. coldsnap

    coldsnap -20 on the money

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    4,297
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    You need to start a thread in the new member forum and tell us what you do in the trade
     
    Rather B Riding and knave like this.
  3. pecmsg

    pecmsg Junior my ASS

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    A good Mechanic knows his limitations!
     
    newtech and Rather B Riding like this.
  4. Chuck

    Chuck SSP

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    Add freon
     
  5. flange

    flange Act like you care and do SOMETHING!!

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    <flat rate> residential troubleshooting flow chart..........replace thermostat if that doesn't fix it, replace capacitors in outdoor unit, if that doesn't do it, replace induced draft fan, if still broke, new board. After that, start changing less expensive parts. 799 plus nonstock parts.
     
    R2D2-TX likes this.
  6. knave

    knave Undeterred

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    Out for a rip
    Hello
    John Roberts

    Are you the homeowner that owns the home that the homeowner (customer) owns?

    Because your technical lingo is technically different than a technician with technical expertise would use to describe the technical issue you have.

    Couldn't resist :D

    Regards,
    Evan
     
    newtech, Catpower, doc havoc and 6 others like this.
  7. mike1020

    mike1020 entitled millennial

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    I don't want to be that guy, but where are you located where it's cold enough to need heat right now?
     
    Zman and coldsnap like this.
  8. mike1020

    mike1020 entitled millennial

    Messages:
    18,168
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    on the roof of target
    John knows how to properly use a multimeter so that puts him ahead of the pack.

    Like Flange said, half the guys I worked with at The Big M would have never used their multimeter and then just put a new igniter in, and if that didn't fix it they would change out the board, lol
     
    Catpower, knave and coldsnap like this.
  9. johnroberts

    johnroberts New Member

    Messages:
    2
    I solved the problem. Your expertise was was not needed. Inducer pressure nipple was clogged. I won't be charging customer for a new inducer or control board like most of you do for a little clogged nipple!
     
  10. Zman

    Zman Hanging by a Thread

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    The "I know a Guy" State
    Convert to Standing Pilot or use a match!
     
  11. doc havoc

    doc havoc A cunning linguist

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    You've got the wrong forum. I can say with utter certainty that no member of this forum would have changed the inducer and/or control board. You blatantly violated site rules, even after being told by @coldsnap you need to start a new members thread. You no read rules, we no help.

    BTW, do you like ice fishing?
     
  12. Anita sannich

    Anita sannich Exceptionally average

    Messages:
    544
    Location:
    Spokane WA
    Put down your homeowners manual, check out the ladder diagram. Also, find out if your homeowners insurance covers badger damage. You're welcome, in advance.
     
    R2D2-TX, chucko615, Catpower and 3 others like this.
  13. Texas-Tech

    Texas-Tech Official Geezer*

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    duhh
    What a dick, learn to properly diagnose problems instead of throwing parts at it then insulting everyone because your skill level is lower than the soles of your shoes.
     
  14. flange

    flange Act like you care and do SOMETHING!!

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    IMT--in my truck
    You are the best, BUT, everyone here would have checked the make/break of the pressure switch first, long before searching the web for a help forum and then posting here about it. We would have known the sequence on how it works, checked the switch, remove the tubes and checked to see if they were clogged or it had a bad switch, then jumpered it at the start of the induced draft fan to PROVE there was nothing else wrong and the system continued through a heating cycle event, but I digress.
     
  15. NZ All Blacks Fan

    NZ All Blacks Fan Just Another swinging Dick

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    yeah what he said. I did see this thread shortly after you posted it (look at the view count) but I refrained from posting because you cant follow site rules and instead waited and did not jump to conclusions like you did about the group here ps I knew what was the likely cause ( aps) hahahhahahahhahahha Ive been doing this for 35 yrs ( since standing pilots and natural draft furnaces) Ive seen the progress from that to 95% ers
     
  16. pecmsg

    pecmsg Junior my ASS

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    Eastern LI
    :boid:













































    :D
     
    Rather B Riding likes this.
  17. Catpower

    Catpower The Crowd Pleaser

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    Glad you got it fixed John, now you can get back to you seat at the Supreme Court:thumb:
     
  18. chucko615

    chucko615 Banned camp counselor

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    I must really be a slacker, I missed this. Great badger reply Anita. ...:thumb: and limitations that was good too.
     
  19. Texas-Tech

    Texas-Tech Official Geezer*

    Messages:
    17,598
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    duhh
    :banned:
     
  20. jamesyarbrough

    jamesyarbrough Amateur Gynecologist

    Messages:
    3,707
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    Denison TX
    Fag
     
    Rather B Riding likes this.