Page 1 of 3 123 LastLast
Results 1 to 13 of 31

Thread: ductwork issue

  1. #1

    ductwork issue

    Hello

    I moved into the house I currently live in 4 years ago. Over the past winters and summers two rooms were always hotter in summer, cold in winter, one of those rooms has my thermostat in it!

    This is an old house, three stories, with a furnace in the third floor and in the basement.

    the ductwork for all of the second floor where the problem is originates in the third floor attic space and then has to travel across the attic down the walls and out to the rooms.

    I have called no less than 3 people to resolve the issue without results.

    So here is what I have figured out, the main trunk is 12 inches and comes off in the attic, it has a few branches to other rooms that work fine, but attached directly inline to the main trunk is a 10 inch flexible line that travels and then drops down the wall, it then is split in the celing of the second floor to multiple vents that are in the ceiling of the two rooms.

    Origionally the 12inch trunk had a 8 inch takeoff installed on it taped to a 10 inch flexible line.

    I dont know if that is how it is supposed to be done, but I took it off, and put a 10inch takeoff on instead and reattached the 10inch flexible duct, and then sealed the flexible line back on.

    No major change.

    These vents produce nothing or next to nothing in terms of air flow and I think this may be simply too far in terms of airflow to get adequate heating and cooling.

    A few questions

    Are flexible insulated ducts a good product for this application, and do they reduce air flow?

    Would a booster fan do the trick installed close to where the duct drops down the wall?

    Can I wire the booster fan to the control board humidifier connection and a hot line so it only runs when the blower operates?


    thanks for any help

  2. #2
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,804
    Well, my first question would be this. Who are the three people who looked at it, and what did they recommend?

    My spider sense is telling me that you did not like what you were told.

    Has any work been done by a professional to fix this?

    Note: read the rules on DIY. We don't do that here.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  3. #3
    Join Date
    Sep 2007
    Location
    Boise, ID
    Posts
    4,326
    Quote Originally Posted by ajtalorico View Post

    Are flexible insulated ducts a good product for this application, and do they reduce air flow?

    Would a booster fan do the trick installed close to where the duct drops down the wall?

    Can I wire the booster fan to the control board humidifier connection and a hot line so it only runs when the blower operates?


    thanks for any help
    Flexible duct's are used all the time in resi work and are rarely sized or installed correctly. They are much more restrictive than sheet metal or fiberglass.

    A 12 inch duct sounds small for a main takeoff but not knowing anything about the size of the equipment, routing and lengths of runs, what do I know.

    Booster fan's can help but should be a last resort. If this is an old house, how well sealed is it and how good is the insulation?

    What did the other guys say?
    If a nation expects to be ignorant and free, in a state of civilization, it expects what will never be. (Thomas Jefferson 1816)

  4. #4
    unfortunately the professionals are choosing not to address it.

    I have paid three people for service calls at about 100 a pop and 0 results.

    not one of them even bothered to go into the attic, although one said he would have someone call me when he saw that there was no airflow coming from the vents. I never got that call.

    I may be able to get someone to spend a bit more time, now that the heat is breaking, but I think they are more interested in quick hitters than actually resolving the issue.

    im not a novice, I have remodeled 4 homes, and did two additions, wiring plumbing etc, so I am not out of my element, and i feel like I have been screwed over thus the frustration and posting here.

    the long and short of it is, whoever installed the system did a bad job, and did not properly calculate the air flow in the bed rooms.

  5. #5
    Quote Originally Posted by Gib's Son View Post
    Flexible duct's are used all the time in resi work and are rarely sized or installed correctly. They are much more restrictive than sheet metal or fiberglass.

    A 12 inch duct sounds small for a main takeoff but not knowing anything about the size of the equipment, routing and lengths of runs, what do I know.

    Booster fan's can help but should be a last resort. If this is an old house, how well sealed is it and how good is the insulation?

    What did the other guys say?
    the house is very well insulated, in fact an entire house was framed and insulated inside of a double brick home.

    windows ect are good vinyl double pane ect.

  6. #6
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,804
    Quote Originally Posted by ajtalorico View Post
    unfortunately the professionals are choosing not to address it.

    I have paid three people for service calls at about 100 a pop and 0 results.

    not one of them even bothered to go into the attic, although one said he would have someone call me when he saw that there was no airflow coming from the vents. I never got that call.

    I may be able to get someone to spend a bit more time, now that the heat is breaking, but I think they are more interested in quick hitters than actually resolving the issue.

    im not a novice, I have remodeled 4 homes, and did two additions, wiring plumbing etc, so I am not out of my element, and i feel like I have been screwed over thus the frustration and posting here.

    the long and short of it is, whoever installed the system did a bad job, and did not properly calculate the air flow in the bed rooms.

    While I appreciate your experiences, the standard we apply here is whether or not someone is an AC pro. I'm sorry to hear that the guys you brought in chose not to address the issue.

    I'd recommend checking our map to see if there is a pro in your area who WOULD be willing to help you.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  7. #7
    Join Date
    Jun 2010
    Location
    Philadelphia PA
    Posts
    2,190

    Unless your 3rd floor unit is a one ton

    The 12" main that goes to a 10" that used to be 8" sounds like the problem, but you already knew that. Unfortunately the OWL Flex system approach was put forward as the final solution to ductwork design. And what we see is the result of that misguided and misunderstood approach.

    Get so real trunk duct and salvage what you can and since you have GC skills the issue of cutting some surgical holes to retrofit a system that delievers shouldn't be a stretch for you.

    Stop being polite, tell these guys you need a ductwork evaluation with a sketch of the existing and a proposed "FIX" If they can do that then pay them and stop asking for some general appraisal. The fact that 3 times and you still don't have an answer is your fault. Really surprising since the implication is that you are in the building trades and should know better
    You have got to learn from other people's mistakes! Because God knows you don't live long enough to make them all yourself !!!!!!!!

  8. #8
    Quote Originally Posted by genduct View Post
    The 12" main that goes to a 10" that used to be 8" sounds like the problem, but you already knew that. Unfortunately the OWL Flex system approach was put forward as the final solution to ductwork design. And what we see is the result of that misguided and misunderstood approach.

    Get so real trunk duct and salvage what you can and since you have GC skills the issue of cutting some surgical holes to retrofit a system that delievers shouldn't be a stretch for you.

    Stop being polite, tell these guys you need a ductwork evaluation with a sketch of the existing and a proposed "FIX" If they can do that then pay them and stop asking for some general appraisal. The fact that 3 times and you still don't have an answer is your fault. Really surprising since the implication is that you are in the building trades and should know better
    agreed, I know better. unfortunately most of the service calls were my wife calling them when I was at work, and me giving in to save my eardrums.

    now that i have actually gone into the attic I see the issue, and from what it looks like to me, there is no way air is going to make it all the way down that long flexible line,

    My idea was a booster fan, but I was also debating running 10inch trunk through that OWL line so at least it is insulated and then use a booster at the furthest point from the main before the duct runs down the wall?

    does that make sense?

  9. #9
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,231
    women often get the runaround with these issues.
    not always, but it happens.
    maybe call back when you can be home to go into
    attic with ac company.

    best of luck.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  10. #10
    Join Date
    Sep 2009
    Location
    Arnold mo
    Posts
    3,969
    I'm interested about these 3 companies who came out and couldn't deliver an answer to the complaint. Are they licenced HVAC contractors? Handyman type of people?
    Specifically, did the OP here contact 3 different licenced HVAC contractors and neither one of them had a clue?
    An answer without a question is meaningless.
    Information without understanding is useless.
    You can lead a horse to water............
    http://www.mohomeenergyaudits.com

  11. #11
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,804
    Quote Originally Posted by tipsrfine View Post
    I'm interested about these 3 companies who came out and couldn't deliver an answer to the complaint. Are they licenced HVAC contractors? Handyman type of people?
    Specifically, did the OP here contact 3 different licenced HVAC contractors and neither one of them had a clue?
    That is my number one question, as well.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  12. #12
    Join Date
    Sep 2007
    Location
    Boise, ID
    Posts
    4,326
    The problem with a booster fan is that without a full understanding of what your total external static pressure is and what your blower is capable of it's a stab in the dark as to sizing it properly....and it's a bandaid to what is really going on.

    You need a pro that can evaluate, and calculate what size ducts need to be there. None of this "a six inch duct is only good for 100 CFM and an eight is only good for"...blah blah blah. The longer the duct duct runs, the more fittings there are, twists and turns, the greater your total external static pressure will be. A 12 inch take off may be fine if it's only 4 feet but if it's 15, that's another story. It's not the size of the duct that counts, it's the sum off all frictional loss and matching it against the manufactures blower wheel curve that counts.

    And don't use flex off the main trunk if at all possible. Go with spiral or rectangular sheet metal.

    Did you do what TB suggested and look at the contractors map?
    If a nation expects to be ignorant and free, in a state of civilization, it expects what will never be. (Thomas Jefferson 1816)

  13. #13
    the more i read here the more i think my situation is a total disaster.

    there is flex everywhere, in fact its predominantly flex even the main takeoff is flex as far as I can see, and I think this is because of space limitations.

    then there is a metal trunk inside it ,then the flex again.


    I imagine its a lot easier to manipulate flex than galvanized in a tight place, and thus the shortcut of flex.

Page 1 of 3 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event