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  1. #1
    Join Date
    Apr 2019
    Posts
    3
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    Faint smell when smelling inside furnace vent

    I dropped something on top of furnace in basement. When I reached over to get my nose went across vent in picture. Smelled slight gas. Heater hadnít come on for about 2 hrs. Opened cover of heater and used a basic gas wand I bought at Home Depot. It went off showing slight gas on first tube/burner in other picture. So I turned gas feed valve off. Had local hvac friend look at it and couldnít find anything wrong. He didnít do any elaborate testing though. He said it could be gas valve inside furnace not closing all the way leaving some residual gas smell. Iím looking to see if anyone has seen this before ? Leaving gas off. Weather is warm enough where I wonít need anyway. Could it be internal gas valve? Or heat exchanger? Links to pics below. One is the vent I smelled gas through. Other are the tubes I was talking about.

  2. #2
    Join Date
    Sep 2008
    Location
    VA
    Posts
    3,555
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    NO DIY advice will be given.

    It's in red letters at the top of the page.

    If you're concerned call a professional technician to diagnose the issue.
    If your friend is a tech, have him perform a professional diagnosis.
    "The only true wisdom is in knowing you know nothing" Socrates

  3. #3
    Join Date
    Apr 2019
    Posts
    3
    Post Likes
    Thread Starter

    Fresh Air Intake Vent Smell After Unit Shuts Off

    I dropped something on top of furnace in basement. When I reached over to get my nose went across vent in picture. Smelled slight gas. This was for a few hours after heater went off. Went away after a few hours though. Had local hvac friend look at it and couldnít find anything wrong but did notice the slight smell as well. He said it could be gas valve inside furnace not closing all the way leaving some residual gas smell if anything. He used a manometer in the gas valve Or could just be residual gas from the unit running. Iím looking to see if anyone has seen this before ? Leaving gas off. Could it be internal gas valve? Or heat exchanger? Or just residual smell from unit.

  4. #4
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    24,459
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  5. #5
    Join Date
    Jan 2004
    Location
    PA
    Posts
    78,022
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    Merged your threads.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Mar 2018
    Location
    Chico, Ca #StateofJefferson
    Posts
    1,365
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    No pictures I've found in that weird rabbit hole of merged threads but a friend would have verified if the gas valve was leaking or not, at least I would, maybe your on your friends bad side
    It is normal in my experience to smell the residue of natural gas having been burnt but it's very faint to me, only noticeable if your face is real close to, say a flue pipe. The best way to know for sure would be to have a fall furnace maintenance performed by an hvac contractor that is trained in combustion analysis.

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