Furnace won't turn back on after lowering the temperature, what to check?

Discussion in 'General Plumbing Help' started by Mystery, Mar 11, 2019.

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  1. Mar 11, 2019 #1

    Mystery

    Mystery

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    This is a fairly new Goodman forced air furnace.
    I replaced it in 2014 or end of 2013.
    All our bedrooms are upstairs where it gets pretty warm even when it's cold outside without heater.
    We hardly need any heat at night so I reduced it yesterday to 60.
    However, when I woke up, the temperature on the first floor was 53 so I checked the thermostat and it's at 60 but heater is not running.
    I tried turning off/on several times, increased temperature, reset thermostat etc... but nothing.
    I turned the fan to On instead of Auto and I hear fan is running but no fire in the furnace.

    What to check? Is thermostat bad?
    Is there a way to test it by jumping the wires behind?

    I read filter and fuse can also cause this issue.
    If fuse is out, fan wouldn't turn on right?
    Is the igniter bad?

    I want to check few things I can before calling professional help as they are pretty pricey, specially when it's cold outside.
    thanks for suggestions.
     
  2. Mar 11, 2019 #2

    frodo

    frodo

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    Just call me Macgyver Professional Supporting Member

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    first, replace the filter

    when was the last time you did that? needs to be done 1x each month

    2nd. unit should have an led light , if it blinks when you turn it on
    count the blinks, consult your literature for the
    problem .it will tell you. one blink for....2 for......
    if you do not or have lost your literature
    look online using product name and model number
     
  3. Mar 11, 2019 #3

    Mystery

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    Thanks for reply frodo.
    Filter was replaced end of December so few months old.

    Not sure if I saw/noticed a light there before. I'll check tonight.
    On the electric switch, there's a small round fuse and I hear click when I turn it off/on.

    Today is not bad but next few days will be snowing and cold.
    I'll grab few extra space heaters from the store just in case.

    I'll take a photo of the furnace tonight and update.
     
  4. Mar 11, 2019 #4

    frodo

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  5. Mar 12, 2019 #5

    Mystery

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    I checked the filter and igniter.
    Igniter read 444 ohms so I suppose that was good.
    However, it had some white layer built up near the tip.

    I scraped it to clean and it broke. :(

    [​IMG]

    Lesson learned: don't clean the igniter.
    I checked local stores and none of them have this coorstek igniter.

    I should have checked the LED's first for errors, huh???
    I noticed the LED only after removing the bottom panel.


    Anywho, now I definitely need igniter.
    If that was the issue, great.
    If not, then I am out one igniter.
     
  6. Mar 12, 2019 #6

    TomFOhio

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    Do you have any plumbing & heating supply houses near you. If not get on-line with your model number and
    get one ordered soon or its going to get cold in the house.
     
  7. Mar 12, 2019 #7

    WyrTwister

    WyrTwister

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    We have a Goodman gas 90% or 92% condensing furnace that is at least 25 years old . In that time , we have replaced 2 hot surface ignightors . Not a big deal .

    Wyr
    God bless
     
  8. Mar 12, 2019 #8

    Mystery

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    I'm not aware of any HVAC supply stores near by.
    I already ordered one online but won't be here until Friday.
    That's also if ignitor is the issue.
    I may have broken good working ignitor.

    For some stupid reason, local walmarts and homedepot are out of space heaters.
    They replaced them with fans for the summer already.

    I have 3 space heaters so no problem for the bedrooms but will be cold in other places.
    I'll get couple more today if I can find them for downstairs.
     
  9. Mar 12, 2019 #9

    WyrTwister

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    Do not be surprised if you start tripping circuit breakers .

    Since the furnace is new , I expect you plan on keeping it for a long time . So , I suggest you consider buying a spare .

    I consider them to be something that goes out every 5 - 10 years .

    I am lucky , the company I work for has accounts at several HVAC distributors . The one I replaced was ~ $ 35 at Johnstone Supply .

    Mine also has a safety device to prove there is combustion air flow / pressure , that the flame successfully lit and I can not remember what else .

    I suggest you do a google search for local HVAC distributors that carry parts , especially for your brand , Goodman .

    Wyr
    God bless
     
  10. Mar 12, 2019 #10

    Mystery

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    Thanks for reply.
    Model is GMS81005CN.
    Here's the innards:
    [​IMG]
     
  11. Mar 12, 2019 #11

    frodo

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    how many blinks of the led is the broken igniter?
    :D:p:rolleyes:
     
  12. Mar 12, 2019 #12

    Diehard

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    It happen between blinks!;)
     
  13. Mar 12, 2019 #13

    WyrTwister

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    Is there a wiring schematic glued to one of the sheet metal covers ?

    Wyr
    God bless
     
  14. Mar 12, 2019 #14

    WyrTwister

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  15. Mar 13, 2019 #15

    WyrTwister

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    Have you installed the new ignightor , yet ?

    Wyr
    God bless
     
  16. Mar 13, 2019 #16

    Mystery

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    It won't be here until Friday.
     
  17. Mar 13, 2019 #17

    WyrTwister

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    Best od luck , :)

    Wyr
    God bless
     
  18. Mar 13, 2019 #18

    Mikey

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    You could try hot-wiring the igniter (jump the two ends with a heavy-duty crocodile clip, or wrap with safety wire) and see what happens. Might give you a clue while you're waiting for your igniters to show up. The documentation cited in the thread gives you a lot to go on. Worst case, it looks like, would be a bad control board ("integrated control module").

    Also, if you've got an electric oven, that would be a dandy source of emergency heat. Not sure if a gas oven would be safe to use -- CO risk?
     
  19. Mar 14, 2019 #19

    voletl

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    When you reinstall your pretty new hot surface igniter and your problems persist. Remove your thermostat.. and take the red wire and the white wire hold them together. If your furnace runs fine then your t stat is bad if it still is broken then you now know its not your t stat
     
  20. Mar 14, 2019 #20

    WyrTwister

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    Best I remember White is the color for heat or 1st stage of heat , on a 2 stage furnace . At the furnace , measure the voltage from white to common , blue or black . Set the tstat high and if you have ~ 24 VAC , the tstat is working .

    On older systems , not uncommon for the common not to be present at the Tstat .

    Wyr
    God bless
     

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