Furnace not igniting- theories?

Discussion in 'The BS Topic' started by FreedomPenguin, Sep 20, 2020.

  1. Dan Videoman

    Dan Videoman Member

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    Your intake air is probably plugged. Bird or bee's nest. Blow out from inside after checking out side.
     
  2. tom3

    tom3 Veteran Member

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    That exhaust and intake has a heat reclaim deal, exhaust heat transfers into the intake air some. I'd guess the intake pipe is clogged up, wasps love those pipes. That's the pipe on the right side of the furnace. Pretty nice setup there too.
     
  3. FreedomPenguin

    FreedomPenguin Veteran Member Lifetime Gold Member

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    I cleaned out the intake, shop vac. Both vents, air passes freely through it. There was no obstruction.

    So that’s not an issue. There’s a couple leds in the safety bottom panel.

    when I crack the lid, runs fine it has 2 lower green lights and upper yellow or orange light

    when it’s sealed up, and doesn’t start.

    there’s 2 green lights. The 2nd one blinks in a series of two.

    Found this trouble shooting online. Since it’s a new filter/no air obstruction and doesn’t light. But it lights up when the case is cracked, I think it’s the pressure switch of some sort.

    going to call some people tomorrow. But fingers crossed it isn’t expensive. The fact that it actually runs just fine when pressure is relieved Atleast gives me confidence Itl be a cheaper fix vs a full blower or something.
     

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  4. FreedomPenguin

    FreedomPenguin Veteran Member Lifetime Gold Member

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    I have full detectors around my house too, hard wired. Combo ones

    no leaks or anything
     
    dave@ztech likes this.
  5. biker

    biker Veteran Member

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    It has to be something simple. What do the LEDs tell you? There should be a legend on a sticker somewhere in/on the furnace to tell you what the lights mean. My gas boiler is 20 years old and has the sticker.

    There is a blower motor for the intake that might be the culprit. I got one cheap on Ebay years ago, fine ever since, exact factory part that I could have bought locally for double the price.
     
  6. danbrennan

    danbrennan Veteran Member Lifetime Gold Member

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    I've had exhaust pressure switch failure a couple of times. One time it actually was the switch, the other time it was the connector to it. I think if the controller sees too much pressure, the gas doesn't flow. The igniter will click for some seconds, then a timer in the controller board shuts it off. Maybe when you open the door the exhaust pressure is somehow relieved? Could temporarily manually open or short the switch - whichever way it goes - or the wires leading to it, put it back together and see if that makes it work. But of course don't leave it like that.
     
  7. FreedomPenguin

    FreedomPenguin Veteran Member Lifetime Gold Member

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    The pressure switch is 50 bucks
    Igniter is 92 bucks
    Blower motor is probably could hundred

    I just dislike how they do the fees and charging here. They want you in this yearly plan, and if you aren’t in it a single visit to diagnose cost almost as much as a yearly fee.

    Keeps the income coming in slow days I guess. It is certainly simple. I have friends with tons of trades, but no gas or hvac
     
  8. Patstuff28

    Patstuff28 Veteran Member

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    I bought my home in 1991. The original furnace lasted until 2017 with zero service calls. I just replace the filter every 3 months with a premium 3M filter. The money I saved by not buying a yearly service contract paid for the new furnace. You will probably be better off without a contract as well. It never hurts to ask the service man if he does work on the side if you ever need him again.
     
  9. FreedomPenguin

    FreedomPenguin Veteran Member Lifetime Gold Member

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    This video is awesome. - I have the exact issue he described. He said is a clogged intake port, but that isn't case for me ,he later goes on to talk about a pressure switch, pretty sure thats my faulty part myself. half tempted to order the 50 buck part and toss it in, see if works. but im less worried after watching this really. im gonna go do the test now, put the cover back on and see if the flame turns off (that will confirm its an intake issue) or if its the switch.

     
  10. biker

    biker Veteran Member

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    Nice work! Diagnosis kinda makes sense, so hopefully you confirm it.
     

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