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  1. #27
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    If I remember correctly, we (as professional HVAC people) can not use that kind of foam as it doesn't meet the flame and smoke spread requirements. You as a homeowner can do what you want in your own home. I would insulate everything into one big ball of insulation, in my own home of course.
    There are two ways to do things, Right and Again.

  2. #28
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    Quote Originally Posted by shavedneon View Post
    If I remember correctly, we (as professional HVAC people) can not use that kind of foam as it doesn't meet the flame and smoke spread requirements. You as a homeowner can do what you want in your own home. I would insulate everything into one big ball of insulation, in my own home of course.
    I'm not sure if you're telling me to go ahead and do it... Or it isn't safe to do it! I'm obviously doing something wrong w/ that duct because I completely took it apart and put mastic on the take off then on the duct, pushed the insulation and foil wrapping and zipped tied it tight. But it's still having condensation. I used that Great Stuff around some others and it seemed to work but now w/ what you're saying maybe I shouldn't have!

  3. #29
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    Quote Originally Posted by MSanchez214 View Post
    I'm not sure if you're telling me to go ahead and do it... Or it isn't safe to do it! I'm obviously doing something wrong w/ that duct because I completely took it apart and put mastic on the take off then on the duct, pushed the insulation and foil wrapping and zipped tied it tight. But it's still having condensation. I used that Great Stuff around some others and it seemed to work but now w/ what you're saying maybe I shouldn't have!
    Go ahead and use what you have, I would do the same at my home.

    If the expanding foam is the same chemical makeup as before it could be a problem with an inspector. The only time it could be a problem in your home, is if your home is already on FIRE. Really I wouldn't worry about it.

    But because this is the Internet and others can read it, that is not the preferred product for profession HVAC people.
    There are two ways to do things, Right and Again.

  4. #30
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    Great Stuff duct insulation will look like a homeowner failed badly at the installation.

    Why not use 3" foil tape and 1" foil faced polyiso foam board to insulate the ducts that are sweating?

    Make it straight, square, and neat. No one ever regrets creating a masterwork.

    PHM
    ------


    Quote Originally Posted by MSanchez214 View Post
    Ok everybody... Here's an update.

    I have moved both blowers to the MED speed and have a noticed a slight drop in humidity. I am now around the 55-60% range. (I have never seen 55% before this). As far as condensation on the unit, I don't have much except for the little at the bottom of the unit which drips into the drain pan (which I still plan on insulating). I do have one duct that I can't seem to stop it from condensing. I have some GREAT STUFF Window and Door w/ the Great Stuff gun as well. Can I just put this all around the duct work and see what happens? Thanks for any advice once again, guys!!!!
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  5. #31
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    Quote Originally Posted by Poodle Head Mikey View Post
    Great Stuff duct insulation will look like a homeowner failed badly at the installation.

    Why not use 3" foil tape and 1" foil faced polyiso foam board to insulate the ducts that are sweating?

    Make it straight, square, and neat. No one ever regrets creating a masterwork.

    PHM
    ------
    This is the part that is sweating... I've tried reapplying the duct work and zip tying, mastic and tape. But still sweating. Might look into your recommendation. Thanks.
    Attached Images Attached Images  

  6. #32
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    What the hell is That mess? I thought you were talking about actual ductwork.

    How did that even get there? I'm sorry - I cannot think of a way to make that right without replacing it.

    To state the obvious: if it's sweating the surface is cooler than the dewpoint of the air surrounding it. To prevent sweating you have to either raise the temperature of the surface, lower the dewpoint of the air surrounding it, or insulate and seal it vapor-tight. Only #3 is viable but I can't think of a way to do that and not have it look like you've left a park bench inside the repair.

    PHM
    ----------


    Quote Originally Posted by MSanchez214 View Post
    This is the part that is sweating... I've tried reapplying the duct work and zip tying, mastic and tape. But still sweating. Might look into your recommendation. Thanks.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  7. #33
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    Quote Originally Posted by Poodle Head Mikey View Post
    What the hell is That mess? I thought you were talking about actual ductwork.

    How did that even get there? I'm sorry - I cannot think of a way to make that right without replacing it.

    To state the obvious: if it's sweating the surface is cooler than the dewpoint of the air surrounding it. To prevent sweating you have to either raise the temperature of the surface, lower the dewpoint of the air surrounding it, or insulate and seal it vapor-tight. Only #3 is viable but I can't think of a way to do that and not have it look like you've left a park bench inside the repair.

    PHM
    ----------
    I thought I was talking about the ductwork. I have flexible ducts. I don't know what this 'thing' is called but it has a main duct coming from the unit into this 'box' which then has 4 smaller ducts going to different parts of the house. The part that has condensation is where the duct and collar meet. I've tried somethings but still haven't solved the issue.

  8. #34
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    Quote Originally Posted by teddy bear View Post
    Why not stay on Med Low. Let it run for a few days. It takes time to drop the %RH because of moisture in the materials inside the home.
    Tape on insulation on any of the sweating ducts.
    Keep us posted.
    Regards Teddy Bear
    Not sure if you saw my update Teddy but here it is...


    Ok everybody... Here's an update.

    I have moved both blowers to the MED speed and have a noticed a slight drop in humidity. I am now around the 55-60% range. (I have never seen 55% before this). As far as condensation on the unit, I don't have much except for the little at the bottom of the unit which drips into the drain pan (which I still plan on insulating). I do have one duct that I can't seem to stop it from condensing. I have some GREAT STUFF Window and Door w/ the Great Stuff gun as well. Can I just put this all around the duct work and see what happens? Thanks for any advice once again, guys!!!!

  9. #35
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    Haven't read the whole thread, so maybe this has been discussed.

    Do you have an attic ventilation fan running? Those fans can pull conditioned air from the house, and the conditioned air gets replaced with humid outside air.

  10. #36
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    Quote Originally Posted by MSanchez214 View Post
    Not sure if you saw my update Teddy but here it is...


    Ok everybody... Here's an update.

    I have moved both blowers to the MED speed and have a noticed a slight drop in humidity. I am now around the 55-60% range. (I have never seen 55% before this). As far as condensation on the unit, I don't have much except for the little at the bottom of the unit which drips into the drain pan (which I still plan on insulating). I do have one duct that I can't seem to stop it from condensing. I have some GREAT STUFF Window and Door w/ the Great Stuff gun as well. Can I just put this all around the duct work and see what happens? Thanks for any advice once again, guys!!!!
    To determine the cooling coil temperature, what is the closest to coil supply vent temp/%RH? Looking for 45^F coil with 75^F, 50%RH. Confirm fan in "auto" mode. No sense adding a dehumidifier to a home with a warm a/c coil and expect efficient results.
    When unable to get down to 50%RH during + 1hour a/c runs, warm a/c coil or excessive fresh air infiltration. A 45^F coil should get 3 lbs. of moisture per hour per ton of capacity.
    You could measure the a/c condensate to confirm amount of moisture removed.
    Thanks for all the info.
    Hope this helps.
    Regards Teddy Bear
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  11. #37
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    Lowering humidity in Houston, Tx

    Just remember during the drier weather, you might want to step up your blower back up to regain the sensible heat removal that you have lost, due to lowering the blower cfm's. Seems like with the condensate issues you are having by lowering the cfm's, a whole house dehumidifier might have been the best route.


    Sent from my iPhone using Tapatalk
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  12. #38
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    Quote Originally Posted by teddy bear View Post
    To determine the cooling coil temperature, what is the closest to coil supply vent temp/%RH? Looking for 45^F coil with 75^F, 50%RH. Confirm fan in "auto" mode. No sense adding a dehumidifier to a home with a warm a/c coil and expect efficient results.
    When unable to get down to 50%RH during + 1hour a/c runs, warm a/c coil or excessive fresh air infiltration. A 45^F coil should get 3 lbs. of moisture per hour per ton of capacity.
    You could measure the a/c condensate to confirm amount of moisture removed.
    Thanks for all the info.
    Hope this helps.
    Regards Teddy Bear
    Teddy, what would you advice be the best way to get this temperature. The closest supply vent would probably be the one in the office. Would I set the thermostat to 75° and let it run for a while before taking the reading. I have some different kinds of thermometers but not sure which one is best for HVAC readings. Also, my condensate line is tied into my laundry room sink. Would I disconnect it from the drain pipe and into a bucket or something for an hour to see how much condensate was collected? Thanks again for all your help!!!!

  13. #39
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    The best meter would be a digital with temp/%RH readings. I would take the reading during hottest part of the day and not the outside conditions. The typical inside temps while noting the space temp/%RH.
    Regarding catching the condensate, note all of the conditions and the amount of condensate during a minimum of 15 mins. and steady state.
    A tech can measure the coil temperature with a refrigerant gauge connected to the coil refrigerant.
    Again best to measure during the heat of the day and noting the actual indoor/outdoor condition, temp/%RH of both.
    You may be at a correct setup, just trying to confirm and the amount of air infiltration via duct leaks and wind. Wind increases fresh air infiltration.
    Regards Teddy Bear
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

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