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Thread: Yucky Ducts

  1. #14
    Join Date
    Nov 2004
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    Naples, Fla.
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    Quote Originally Posted by jeffw_00 View Post
    Ok - I've talked to a couple of local contractors, they'll give me (4-figure) quotes on replacing all the flex duct, but no one wants to approach this incrementally. (I mean, what if the problem isn't confined to the flex?)

    I have a total of 7 20yr old flex supply ducts in my attic, they all start and end in the accessible part of the attic, all off the same aluminum main supply.

    Two are 6" x ~3'
    One is 8" x ~2'
    Three are 8" x ~10'
    One is 8" x ~15' (the yucky one)

    Point is, they're mostly real short.

    I'm thniking I'm going to get some flex duct and ties, wait for a cool day, and start pulling off the flex myself to see how extensive the problem is. Assuming the main supply looks clean, when I pull a duct, if it looks 'yucky' I'm going to replace it on the spot.

    To be honest, if I could find someone who would be willing to rent me their duct guy hourly (and I understand the hourly rate could be 3-figures), to do this sort of "inspect and replace" in one visit, I'd actually prefer to take that route. I don't want to do it myself. But no one wants to keep it simple.

    And it seems like it should be simple. I mean, if the muck is confined to the flex, this should do it. If i see muck in the main supply box (is that likely?), then I should stop, accept that I'm hosed, and get quotes to replace ALL the supply ductwork sheetmetal & flex. (maybe the flex should be replaced with rigid insulated aluminum duct, which I believe is more common today?).

    anyway - how would you go about this if you didn't want to make a big project of it? Unfortunately I live in a town with some very wealthy sections. I'm not lucky enough to live in one of them, but local contractors seem to think of this as a "white glove" town, and the stock response is to just rip everything out and start over 8-{

    thanks!!
    /j

    Your ideas of a "remedy" are grossly insufficient. Removing the contaminated duct does not cure the problem, its like putting a clean bandage on a cancerous lump. If you fail to address the correct clean up procedure and bring remedy to the cause of the problem - the problem will remain or get worse.

    You won't find anyone in their right mind to sub out their labor, you won't find anyone in their right mind to simply remove the 15' of slimy duct.... when someone in your home comes up sick --- you'll be the 1st one to hire an ambulance chaser to sue the pants off the grossly incompetent contractor you hired that should have known better.

    Unfortunately this is not a DIY site or a training form, for the most part you have experienced contractors trying their best to offer sage advice.

    You have described a serious situation that requires professional remedy.

  2. #15
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    You know. what's going on here is that i have a problem, and I've come to this forum so that I understand it, so that when I get professionals in to fix it, I can make sure it's done right. If you read my other posts, you may begin to understand why I feel I need to be educated. (I found this forum after I blindly took bids, and hired someone, to replace my furnace and A/C, only to discover after the fact that the furnace was 50% too large for the duct system, and the A/C had been installed -sideways- with half the blower outlet blocked off). So I've become paranoid about writing 4-digit checks to someone who's going to 'take care of it' without my ever understanding what they're doing or how they're doing it. In the meantime, you guys have become so unwilling to educate a homeowner because you're paranoid that maybe he'd miss the difference between "understanding" and "having-the-skills-to-do-it", that you don't want to share anymore. To be honest, if every answer on this forum becomes "yup, you have a problem, go hire someone, don't ask questions" it's going to become very repetitive. Believe me, I really, really DON'T want to be crawling around in that attic. But I also don't want to spend a bundle and NOT fix my problem.


    Thanks - that felt better. 8-}

    I don't disagree that what I have may provide "professional remedy", but it looks like if I want a contractor to provide that, it looks like I need to ask for it, as what I'm getting is "oh, we'll just replace everything for $xK". So, what sorts of things might be going on? And what sort of professional remedy might be required?
    Thanks
    /j

  3. #16
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    Quote Originally Posted by jeffw_00 View Post
    You know. what's going on here is that i have a problem, and I've come to this forum so that I understand it, so that when I get professionals in to fix it, I can make sure it's done right. If you read my other posts, you may begin to understand why I feel I need to be educated. (I found this forum after I blindly took bids, and hired someone, to replace my furnace and A/C, only to discover after the fact that the furnace was 50% too large for the duct system, and the A/C had been installed -sideways- with half the blower outlet blocked off). So I've become paranoid about writing 4-digit checks to someone who's going to 'take care of it' without my ever understanding what they're doing or how they're doing it. In the meantime, you guys have become so unwilling to educate a homeowner because you're paranoid that maybe he'd miss the difference between "understanding" and "having-the-skills-to-do-it", that you don't want to share anymore. To be honest, if every answer on this forum becomes "yup, you have a problem, go hire someone, don't ask questions" it's going to become very repetitive. Believe me, I really, really DON'T want to be crawling around in that attic. But I also don't want to spend a bundle and NOT fix my problem.


    Thanks - that felt better. 8-}

    I don't disagree that what I have may provide "professional remedy", but it looks like if I want a contractor to provide that, it looks like I need to ask for it, as what I'm getting is "oh, we'll just replace everything for $xK". So, what sorts of things might be going on? And what sort of professional remedy might be required?
    Thanks
    /j


    OK Jeff - I'm 2,000 miles away - what would you like me to sell you? This is not an easy fix. Offering a remedy w/o a diagnostic is malpractice.

    You have been given sage advice, this CAN be a serious problem, replacing ducts may be part of the remedy.

    Every job, every home, every installation has some degree of nuances or history that make it very unique.

    I'm sorry you've had a bad experience - do contractors in your state require licensing? Did the job get inspected by the city / county?

    If you want professional results - you'll have to hire a professional. Finding that professional is no different than finding an expert in your chosen field. Ask friends, ask your neighbors, ask co workers, look on Angie's list (pls don't bother with the BBB --- its a club).

    As far as what can cause it: -pick one or more of any of the following:

    1) Bad duct work - leaking, improperly insulated. improperly installed
    2) High static
    3) Poor air filtration
    4) The wrong system for the application
    5) The wrong size system
    6) Improper refrigerant charge
    7) Improper match up of system components
    8) Too hot of an attic
    9) Consumer closing off vents in home
    10) Consumer opening windows
    11) Water leaks in your home
    12) Poor hygiene in home (do you store dog food near the return air?)
    13) Roof leaks or construction deficiencies (was the home ever flooded?)
    14) Malfunctioning blower
    15) Dirty blower wheel
    16) Obstructed duct
    17) Animals living in the duct
    18) Clogged evap coil.
    19) Evap fan running backwards
    20) Improper wiring / controls set up
    21) ???
    22) ???



    That's why I suggested --- have your air tested by a contractor that utilizes Air Advice. Its a starting place, once this plus a myriad of other diagnostics are made ----- then an experienced professional can build you a remedy, until then you're just changing parts.

    Often times - it makes sense to stop the nonsense, get a load calculation recruit an expert, ask for referrals & execute while holding a contractor responsible for results.

    Sorry to have disappointed you.

  4. #17
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    burlington county n.j.
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    #21 it is a house in the northeast US that has an attic duct system used only for a/c.

    i would be willing to bet that water condenses on the inside of the ducts in the winter time and that is what caused what you found....

  5. #18
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    Jun 2005
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    New England
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    you haven't disappointed me - that's a start. Answers
    1) I think contractors have to be licensed, but no inspections.
    2) The system is a 2-year old Bryant Evolution. In the process of fixing the installation issues, the new contractor determined that system is properly sized and static is ok (0.67 on high blower). Refrigerant & coil were checked a couple of months ago. Spacegard filter replaced every spring (I'm in new england). Blower is new and seems to work fine. System operates well in general.
    3) No pets, no bad stuff near returns.
    4) attic has ridge & (cleared) soffit vents, but does get hot (up to 90+ Deg F on hot days).
    5) windows are closed, vents are open (dampers open at main)
    6) no water leaks I'm aware of. No roof leaks going back 20+ years.
    7) No obvious leaks in ductwork.
    8) windows stay closed.
    9) No animals in the ducts that I'm aware of 8-} (Had a duck fly down my furnace chimney once though...)

    One thing I'm wondering. As I mentioned, the particular flex that I pulled was the one where I installed an in-duct blower years ago, and I did notice condensation on the outside of the blower when I removed it. I can't help but wonder if -I- did a bad job a decade ago (long before i found this forum so I didn't know better), and the problem is limited to this one duct.... Probably wishful thinking though.

    Other thoughts- A couple of years ago there was a mildew buildup on one register that we cleaned off and didn't recur. It is true that there are some long hot showers taken in our house, and although the returns aren't in the bathrooms, a couple aren't far from the (usually closed) bathroom doors.

    So given all this, if you came to my house, what would be the first few things you'd check?

    Thanks!
    /j

  6. #19
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    Quote Originally Posted by t527ed View Post
    #21 it is a house in the northeast US that has an attic duct system used only for a/c.

    i would be willing to bet that water condenses on the inside of the ducts in the winter time and that is what caused what you found....
    your analysis of the system use is correct. It's also true that we run a (properly-maintained, and thus effective) humidifier in the winter as part of our Forced-hot-AIR system in the basement.

    IN FACT, a year ago December, for reasons I don't remember, I went up and replaced the filter in December. The filter housing had, uniquely, never been insulated, and the inside of it was W-E-T. I soaked a bath-towel wiping all the condensation off the inside. I have since had the housing wrapped with duct insulation, but I wonder how well the 20+ year old duct insulation and insulated-flex is doing it's job on the rest of the system.

    So your hypothesis makes sense. But maybe just replacing what is there isn't the answer. In which case, what can I do?
    Is it cumulative? In which case I'm ok paying to replace the flex once every couple of decades or so (or is the newer stuff less sensitive to this), but is it just the flex or do the aluminum mains also need to be replaced?

    I think you may be on to something here - but what do I do?
    /j

  7. #20
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    Quote Originally Posted by jeffw_00 View Post

    I think you may be on to something here - but what do I do?
    /j

    condensation will form inside the duct over the winter due to the warm house air going up into the cold attic ducts.

    2 things you can do, 1 is to insulate the flex duct with another heavy layer of duct wrap. this solved the same problem in my fathers house 20 years ago.

    the other thing you can do is run the blower in that unit on a timer to circulate air thru there to keep it from condensing.

  8. #21
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    Thanks t527 - although, It's a lot of ductwork to wrap - since the flexes are probably toast, can they just install "double-wrapped" duct? (maybe I should go to rigid duct with a 'double' wrap - is there such a thing?)

    What about the actual A/C unit - should that be wrapped? I mean, do I have to make sure -everything- is double-wrapped?

    What sort of cycle for the blower? When I run the blower in the winter (when it's below freezing outside) it makes the house kind of drafty....

    still - this is having the ring of truth to it....
    thanks again
    /j

  9. #22
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    Run it on the lowest cfm.

    Not sure about the cycles as we don't have that issue here.

  10. #23
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    Sep 2006
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    Quote Originally Posted by jeffw_00 View Post
    Thanks t527 - although, It's a lot of ductwork to wrap - since the flexes are probably toast, can they just install "double-wrapped" duct? (maybe I should go to rigid duct with a 'double' wrap - is there such a thing?)

    What about the actual A/C unit - should that be wrapped? I mean, do I have to make sure -everything- is double-wrapped?

    What sort of cycle for the blower? When I run the blower in the winter (when it's below freezing outside) it makes the house kind of drafty....

    still - this is having the ring of truth to it....
    thanks again
    /j

    You can special order R10 insulated flex in sizes from 3" - 20" from: www.ancoproductsinc.com

  11. #24
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    Jun 2005
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    New England
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    So you guys have me thinking that I what I need to do is
    1) replace supply flex with heavily-insulated flex
    2) "clean out" any mold in main supply trunk (not sure how this is done, but contractor should know?)
    3) double-wrap main supply trunk
    no work on returns - filter will keep stuff in returns from passing into supply

    but I had my semi-annual checkup with my allergist (Senior guy at MassGeneral in Boston) yesterday. He said "sometime this winter, when it's really cold, turn off your humidifier for a day or two, and the dry air will kill all the mold. No need to replace anything".

    So now I'm really confused 8-}

    Still - does my original plan (nothwithstanding finding another cause when the work is done) make sense?

    /j

  12. #25
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    Jan 2004
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    Your ducts in the attic, will always have a high RH then the house.

    So if your house is at 20%RH, the ducts in the attic could be 55%RH.

    Replacement of flex sounds good.

    I would also put a block of sometime in the return grille, and stop the flow of air from going through the ducts in the attic.
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  13. #26
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    Hi BT - thanks - but there are actually 6 returns - although I suspect the problem is humidity directly rising into the supply ducts (as the blower doesn't run in the winter). I thought about closing all the supply registers in the winter, except a couple aren't adjustable or can't be easily reached (one is 12' up a sheer wall). None of the returns have adjustable registers, and none of the dampers are at the register, they're all at the taps from the supply trunk.

    If it's simply a matter of killing airflow in the winter, we could put a damper at the main return (or simply wrap the spacegard filter in plastic and slide it back in). But I think I would have to somehow isolate all feeds/returns and that's a lot of things to block.

    /j

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