Flue pipe through thte supply plenum - Page 2
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  1. #14
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    Sep 2003
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    Ok, now explain a little to me. Is the flue going into or through the plenum? If going through the plenum, am I right in seeing that the flue has been physically isolated from the plenum air? You say that the "passageway through it was two duct collars with foil tape which had failed"; Where was the foil tape, sealing the 2 collars about midway between, which would be out of sight in this picture?

  2. #15
    Join Date
    Apr 2002
    Location
    Texas
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    165
    Plenum measured approximately 20 inchs wide by 8 inchs high. Two holes were cut in it, top and bottom, into which two duct collars were inserted - one from the top and one from the bottom. No sealing material was used at the fingerjoints of the duct collar but foil tape was used to seal the location where the two collars met. The tape had failed during the year the unit was in place leaving approximately 1/2 inch of open space where the collars did not meet.
    Frank

  3. #16
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    Sep 2003
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    1,311
    No doubt that it was crass to suppose that foil tape is the perfect item to fill a 1/2" gap. However, there is nothing wrong with installing a sleeve through a duct so that the duct air is physically isolated from the room. It would be along the same line of installing 2 duct Ys end-to-end so that the duct split then joined back together - and then running a flue pipe through that split. Once the collar is properly installed (such as using only a single piece of hard pipe so that there is no air leakage) you can run whatever you want through the sleeve as long as it is within code as though you were running the object next to the duct. A flue is no exception - it can correctly be ran as noted; The only problem here was that the installers did not seal the collars and tried securing the 2 collars together with foil tape. "[P]eople most be dropping like flies"? The installation as seen is no different than if the flue pipe was running next to the duct and there was a 1/2" gash in the duct blowing on the flue pipe. Would that kill anyone? no. It appears that there was quite a misunderstanding on the concept of what was done.

    Legal discalimer: I did not perform the install and I have no knowledge of being affiliated with the original installers in any way at any time.

  4. #17
    Join Date
    Apr 2002
    Location
    Texas
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    165
    Actually, we examined every method to correct this problem without a lot of additional expense. It was an insurance job and the insurance company had to replace the unit becase mold was growing in the place. Additional problems were that it was a four ton unit on a 1300 sq ft 2-story. There were only 6 registers in the whole place and standing in front of one would blow your hat off.

    The Mesquite, Texas building officials would entertain no instance of the flue penetrating the plenum, and if you read the IMC it is not allowed. Remedy in this case was to install 90% furnace.
    Frank

  5. #18
    Join Date
    Sep 2003
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    1,311
    I'm not saying there was error in choosing to replace the unit by any means. I was merely pointing out what appeared to be a misunderstanding for everyone's benefit. By the posts made it appeared that many of the guys didn't understand the goofy way of running the flue was OK.

    It is true that a flue cannot penetrate a supply air. The flue wasn't penetrating a supply air, though; The collars were penetrating the supply air. The flue being ran through the collars is not the same as the flue making a direct penetration through the duct. I once had the very same objection while working for a certain employer (and the immediate supervisor was an engineer) - I guess you see who won.

    I support your decision to proceed in the manner that you proceeded. I did not mean to imply that you should have left the furnace alone or reinstalled an 80% furnace. I was just trying to point out that it was not as dangerous or out-of-code as thought.

  6. #19
    i guesse there trying to get more heat .

  7. #20
    Join Date
    Nov 2000
    Location
    Waco, Texas, USA
    Posts
    6,153

    Thumbs down

    The reason is the ductwork is all ran in fur downs and never goes in the attic. The plenum space in front of the furnace must be used to hit the fur down area.

    What happens when the customer calls a legitimate licensed contractor to replace the old furnace? Any upgrades to change the flue path would cost extra money. The customer would compare bids and go with the low price guy that never pulls any permits.

    "And remember my sentimental friend......that a heart is not judged by how much you love, but by how much you are loved by others" - Wizard of Oz.

  8. #21
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    Feb 2004
    Location
    Indianapolis, IN.
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    Common sense not being a birthright, statistics report "stupid" may strike one in three.

  9. #22
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    Sep 2003
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    So what's your point?

  10. #23
    Join Date
    Feb 2004
    Location
    Indianapolis, IN.
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    Well, if one were to put an insurance companys' risk management attorneys up against an Engineer, I believe we can ascertain the outcome. follow the $$$$. (Always). I can certainly appreciate the point of the "sleeve" my good man, I've had similar decisions to weigh; however, why take such an uncertain risk?

  11. #24
    Join Date
    Sep 2003
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    1,311
    Where's the risk if the vent pipe is installed with the proper clearances from combustible materials? There was no mention of vent pipe being upside down and no mention of pipe joints not being fit together properly. For a lawyer to prove liability he would have to prove that it was wrong; He could prove that it was wrong to apply tape to seal a 1/2" gap, but he cannot prove it is wrong or improper to fabricate a duct with a 6" sealed sleeve that penetrates said duct. He also could not prove that it is wrong or improper to run a type B vent through a sleeve provided that required clearances are maintained. Since he cannot prove it is wrong or improper then it would be normal and correct for the defense lawyer to move for dismissal with prejudice, court costs, and lawyer fees on the grounds of the case being without foundation and without merit.

    Here's something to consider: Whould it be improper if, instead of a sealed pipe penetrating a duct, the duct split in to a 'Y' which was then connected to another 'Y' end-to-end so that the end result, once installed, was a single duct that splits then joins back together and continues as a single duct? Why or why not? If that is OK to do, then would it be OK to run a type B vent through that area where the ducts were split? After all, the air in the duct is still totally isolated from the room. If it isn't OK, then why? If it is OK, then why would it be wrong to make a 1 piece 'Y' with the split in the middle (which is essentially what is pictured except for the lack of proper sealing) rather than a 2 or 3 piece 'Y'? What would be the difference?

    Codes regarding running a flue through duct refer to the flue being in direct contact with the duct air. But once the air leaves the duct then it is no longer duct air, but rather free air. The air that is in contact with the flue pipe in the picture is free air, not duct air. If it were a violation for free air to contact a flue pipe then a flue could not be ran in a furnace room where there is any ducts at all. In the picture posted, though, it could be argued that after some of the free air hits the flue pipe (free air from the 1/2" gap in the collar) it can return to the duct and become duct air again because of the possibility of a vacuum being created on the trailing end of the collar, thus it is a code violation. I do not disagree with such a claim. My statements are based upon a properly installed collar, not the one seen in the picture. I agree that it is best to avoid doing what is picture, but aside from not being properly sealed, I do not see any code violation or dangerous situation.

  12. #25
    Join Date
    Feb 2004
    Location
    Indianapolis, IN.
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    Talking

    Ok, you win, game, set, match. Go ahead and do it that way it's ok be me just as soon as you sign on your companys' letterhead that it will last forever without any incident or risk of failure at any time. I have found few technicians, Engineers, Plant managers, or Service managers willing to do that. That they will accept all liability for the equipment, the complete connected loads, and any and all temperature and humidity sensitive valuables which the equipment will be managing, and of course the occupants of the space. I'm sure it will work out fine...

  13. #26
    Join Date
    Feb 2004
    Location
    Indianapolis, IN.
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    23

    Talking

    Originally posted by tempro
    Ok, you win, game, set, match. Go ahead and do it that way it's ok be me just as soon as you sign on your companys' letterhead that it will last forever without any incident or risk of failure at any time. I have found few technicians, Engineers, Plant managers, or Service managers willing to do that. That they will accept all liability for the equipment, the complete connected loads, and any and all temperature and humidity sensitive valuables which the equipment will be managing, and of course the occupants of the space. I'm sure it will work out fine..."The first thing I learned was to forgive myself; then I told myself "Go ahead, do whatever you'd like, it's OK by me" (Unknown)

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