How to open dampers in finished garage ductwork
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  1. #1
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    Dec 2007
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    How to open dampers in finished garage ductwork

    I guess a better title would be "how to adjust damper in finished garge ductwork"

    The registers in the upper level of my split level house blow very little air.

    While they are blowing and for a few minutes afterwards I can hear a slight clanging sound.

    A friend suggested that there could be a damper that is stuck.

    He suggested that I cut a hole in the sheetrock and shine a light to see if I can see a damper in the heat run

    He doesn't give very good explanations and can't come over to help.

    I can't picture what he is talking about.

    My garage has a long area of ductwork that is sheetrocked. I cut a small hole in the sheetrock but I can't figure out how to look inside. Is there an open area in the ductwork or something that would allow me to see inside?

    I'm also not sure what he means by "heat run".

    Thank you for any suggestions or help.

    John

  2. #2
    Join Date
    Dec 2007
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    MA
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    There could be many problems here. On a typical duct system you have a main trunk, and individual runs that attach to the main trunk. Typically if installed properly you would have dampers on each individual run to be able to properly balance the system. If a portion of the main trunk is going to be covered by a hard ceiling, putting dampers in the runs would be useless. A balancing damper in the main trunk, just before the duct is covered by the ceiling would be the best way to control those runs. It sounds to me if you are have problems with multiple runs, its probably not a damper issue, but more likely a duct design issue. Unfortunately the only way to really find out is get access to all the duct by removing the hard ceiling. Cutting holes to try and find dampers that may or may not exsist, or may or may not be open or closed seems to be a waste of time. I would recommend calling a profesional to try to asses the problem before cutting a bunch of holes. If you are going to cut holes, but don't know what your looking for. Why don't you look at your exposed duct work to see if you can find a damper. Then you'll at least know what your looking for before you cut any holes

  3. #3
    Join Date
    Jan 2004
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    Lancaster PA
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    You'll have better luck removing the supply reg. Putting in a bright flash light, and using a mirror to look for a loose damper.

    Your way, you'll be cutting a hole at every suuply run to look.
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  4. #4
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    Dec 2007
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    Thanks to both of you for replying.

    Unfortunately there is no area with unfinished ductwork except for a small part in the basement where the ductwork comes off the furnace.

    I'll try the idea with the flashlight and mirror. I tried it before with no luck but I'll try it again.

    John

  5. #5
    Join Date
    Sep 2002
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    Boise Idaho
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    Just so you know, that hole you cut in the sheetrock just breached the fire rated seperation from your garage to your house (1 hour rating). You would have better luck callling a company out to take a look at it. Tell them over the phone what your problem is and see if they could send a Tech with sheetmetal duct experience. He could help you find what you are looking for and save you from swiss cheesing that sofet. In addition to that I doubt you have dampers, most resi has none.


    matt

  6. #6
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    [QUOTE=Mstrav;1700950] In addition to that I doubt you have dampers, most resi has none.

    That all depends on the region. Here in New England its uncommon to find a residential system with out dampers.

  7. #7
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    he doesnt say what part of the country he's in, but I would still say majority have none. Some regions it may be standard. (the register doenst count as a damper, refering to in line at the branch).


    matt

  8. #8
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    Quote Originally Posted by Mstrav View Post
    he doesnt say what part of the country he's in, but I would still say majority have none. Some regions it may be standard. (the register doenst count as a damper, refering to in line at the branch).


    matt
    What area do you work in? And do you use sheetmetal or duct board?

  9. #9
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    Your not suppose to install a damper where it can't be accessed. But that doesn't mean someone didn't install one where they knew it would be drywalled in anyway.
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  10. #10
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    Thank you for all the replies.

    I'm located in the midwest and the house is about 45 years old.

    This house has had some remodeling done to it and some stupid stuff was done in other areas so what you're supposed to do and what is supposed to be done could be worlds apart concerning this.

    John

  11. #11
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    Quote Originally Posted by dsfitzgerald7 View Post
    What area do you work in? And do you use sheetmetal or duct board?
    the only thing I do with ductboard is tear it out. I do almost 100% commercial now, but have done track in the past for companys doing several thousand houses per year, and we used no dampers. Western states mostly. Everything I do has a damper and flaging, but its commercial. In houses it is way more critical to just size it right the first time. He has a 2-story house and he will never be good with one system, especially if it has been scabbed onto over the years by remodels. Only solution is zoning or 2 seperate systems.


    matt

  12. #12
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    I think regardless, turning to a profesional is your only way to solve the problem. I know that some duct cleaning companys have the ability to snake cameras down the duct work. Thats another possibility.

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