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  1. #1

    Furnace not turning on automatically via thermostat. Help!

    This started a few days ago. I had noticed that the exhaust fan would turn on, followed by the burners kicking in... and then I had noticed that a few minutes had gone by the the blower wasn't running.

    I would go to the thermostat and it would read "Heat On", yet wasn't blowing any air. I would switch the thermostat to "off" and back to "heat" and then everything cycled in order and all was good.

    I noticed it did it again last night. I went over to the thermostat and performed the same steps and voila... everything was working again.

    At this point, I figured that this wasn't just a fluke that I should call someone in the morning.

    Sure enough, I wake up this morning to a similiar issue. This time, nothing had fired up, the thermostat was at 66 degrees with it set to 70 and it read "Heat On". No exhaust fan, no burners, no blower. I performed the same steps and it was fine.

    Now its at the point that manually flipping it to "off" and back to "heat" is the only want to get the furnace to work.

    I have a repair guy on the way (should be here any minute), but I was hoping to get some people's ideas what might be wrong before he slaps me with a $500 bill.

    The furnace and house are both 18 months old. This is a bit of a shock to me because this is the first time in my 10 years of owning a home that I've had furnace problems.

    Not sure if this matters, but the furnace is a York.

    Any thoughts? I'm thinking a relay switch on the board... but I'm confused as to why it won't cycle by itself, but will cycle when manually switched.

  2. #2
    Join Date
    Jun 2004
    Location
    Howell, Michigan
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    16,176
    Since your furnace is 18 months old I am quite sure parts may be covered under warranty. You will be responsible for labor. Oh yea, if you haven't done any maintenance you will be responsible for that also.

    We can't offer any DIY advice, since you have a tech on the way out let us know what it was.

  3. #3
    I was hoping that someone might give me an idea of what it might be. I don't play on doing any DIY.... I just don't want to be blind sided by the repair tech. It would be nice to know that it could be a relay switch so that when he comes to me and says I have to spend $2000 on a new furnace, I could be like "hey... couldn't it be the relay switch?"

  4. #4
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    67,880
    Relay switches on furnace controls boards aren't replaceable.

    Get your furnace papers out, and look at your part warranty, to see how long the part warranty is. Its probably 5 years.

    There are several things that could cause your problem, that are furnace parts.

    There are also several things that could cause this that are't furnace parts.

    The tech coming out, doesn't need us second guessing him before he even gets there.
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  5. #5
    Join Date
    Dec 2002
    Location
    Houston,Tx.
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    15,918
    Got to be a Ducane.
    __________________________________________________ _______________________
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  6. #6

    Hmm

    he is claiming that he cannot reproduce it. the only way that i have been able to reproduce it is by letting the thermostat cycle the furnace by itself. he is manually cyling the furnace. i'm sure... in theory... its doing the same thing.

    he did say that the flame sensor was dirty and was going to perform a 31 point inspection and cleaning.

    i hope it helps... otherwise i have to pay for them to come out again.

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    Intermittent problems can be difilcult to diagnose.

    We've all had them, and know how hard they can be to track down.

    Ask him, if your model has the control board, that stores the last 5 faults.

    If it does, he can recall them, and go from there.
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  8. #8

    Thumbs up

    Quote Originally Posted by beenthere View Post
    Ask him, if your model has the control board, that stores the last 5 faults.

    If it does, he can recall them, and go from there.
    Where as I was not looking for someone to solve my issues in a DIY sense, these are the suggestions I was looking for.

    Thank you for your input, but the tech has already left the house. If I need him back, I will be sure to ask this question.

  9. #9
    Join Date
    Feb 2009
    Location
    Ft Madison IA
    Posts
    33
    The thermostats purpose is to tell the furnace when to come on and how long to run.... so if the furnace seems to work consistently when it is adjusted I would make the decision based on what you say that the thermostat is intermittently failing.... tell me this is it a digital or an old mercury type? If it is digital does it has fresh batteries in it? If it is a mercury type it may have to have the heat anticipator adjusted if it is on a newer high efficiency furnace.

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    Newer furnaes have both hard, and soft lockouts.
    May have nothing to do with the thermostat at all.
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  11. #11
    Join Date
    Feb 2009
    Location
    Ft Madison IA
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    hard or soft lock out is irrelevant considering according to ATjaguarX he said the furnace will cycle properly if the t-stat is adjusted manually.... so that tells me the problem is in the control circuit..... All fingers point to the t-stat

  12. #12
    Join Date
    Dec 2002
    Location
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    Quote Originally Posted by wadesquad View Post
    hard or soft lock out is irrelevant considering according to ATjaguarX he said the furnace will cycle properly if the t-stat is adjusted manually.... so that tells me the problem is in the control circuit..... All fingers point to the t-stat
    Quote Originally Posted by ATJaguarX View Post
    I would go to the thermostat and it would read "Heat On", yet wasn't blowing any air. I would switch the thermostat to "off" and back to "heat" and then everything cycled in order and all was good.

    Are you saying this because of this he wrote here? if so it could still be the board.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    Lets keep this thread from going into DIY diagnostics.

    The OP can update us, after a few days if it starts doing it a gain.
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