Results 1 to 8 of 8
  1. #1
    Join Date
    Aug 2011
    Posts
    10

    Red face Air conditioning my yard???

    So my brand new Carrier Infinity 50xt 3 ton packaged heat pump unit is in and seems to be functioning correctly except for this: When I feel below the unit, just below where the center of the supply plenum duct meets the base there is a good bit of cold air definitely flowing out into the great outdooors. This air is not leaking out of the joint where the supply duct is connected to the unit. That joint is flanged and screwed and siliconed well and I feel no air whatsoever there around the entire edge of that joint. This air is escaping the bottom of the unit just before it exits the unit. Reach through the base rail slot and there it is flowing right out the bottom, just inside the base rail where the plastic base meets the base rail. I suspect that both the base and sides are supported by the base rail and the leak is where the side meets the
    base. How is this seal done???

    The floor of the unit is a molded plastic, the sidewalls are sheet metal, and the base rail is galvanized. It feels like the air is flowing out at the edge of the plastic base where it meets the sidewall and/or base rail.

    Has anyone seen anything like this?

    Does anyone know how the air seal is maintained at this point? In particular where the metal side meets the plastic base.

    Is it possible to open the right side of the unit to see this area without taking apart the supply ductwork???

    My installer is going to come take a look and I would really like to give him any info or suggestions that might be helpful.

    One thought that occurred to me is as follows. When the installers screwed the flanges on their fabricated supply duct into the back of the unit (that's how they did it) maybe the screws pushed a piece of the insulation board inward inside the unit. I remember that there was foil tape sealing the board to the supply opening on the back of the unit. Maybe that tape (or similar tape at the bottom of the foil board?) was popped or torn in the process and allows air to sneak between the metal wall and the plastic base if there is a small gap there.

    By the way, the thermostat shows static pressure readings running around 0.25 under low air flow ranging up to around 0.8 for the highest air flow.

  2. #2
    Join Date
    Mar 2010
    Location
    Kent, WA.
    Posts
    192
    Im not sure on your particular unit but in the commercial side of packaged units they can be configured in either side or bottom exit. if you are using the side exit I would suspect the bottom exit block off panel may not have been sealed to the unit.
    Cheap work is not good, good work is not cheap...

    A positive attidude will not solve all your problems, but it will annoy enough people to make it worthwhile.

  3. #3
    Join Date
    Jun 2011
    Location
    Wake Forest, NC
    Posts
    352
    Static pressure readings from your thermostat? Thats pretty slick. BTW, what that guy below me said would be my first guess.
    It's not rocket-science...

    It's electromechanical thermodynamic engineering

  4. #4
    Join Date
    Aug 2011
    Posts
    10

    I think you guys are right - and the fix? Is a fix needed?

    My unit is configured for horizontal discharge as you surmised.

    I can now report more specifically that I feel a very small localized flow of cold air coming straight down from two areas along the opposite edges of the downflow panel cover. The installation manual talks about how these panels are attached like a knockout in an electrical box with "tabs" (Which are hidden from view from below as far as I can tell). I think this is a lot less air than I first thought, the back of my hand is very sensitive to even a small flow of cold air. Maybe the whole base including the covers is molded as one piece of plastic with very thin areas to enable knocking out the downflow base plates where my small leaks exist.

    Incidentally, I put my little mini temperature probe sensor in the leak air and it is 25 degrees cooler than the outdoor air (60 versus 85 F).

    The panels do not look cracked or loose, that was my original worry since the unit is new and just shipped. So I suspect that this is just how they are, not perfectly sealed, but not leaking enough to make much difference.

    I can reach under the base and easily put some silicone on the joint or (ask the installer to do so). After all there is only a half inch of water or so pressure involved so it will probably stop this small leak. I don't think it is necessary for the service people to open up the unit only to find that there is nothing wrong but I am really curious as to what exactly is going on there.

    All my observations are from peering and feeling through the small openings on the metal base frame so its kind of hard to see and feel.

    Obviously it would be best to seal them from the inside where the positive pressure is, but I am not convinced this is going to be necessary.

    What do you think about this? Is a small leak to be expected? Do you know how this panel seal is done at the factory? Are the install techs supposed to glue it in place if horizontal flow (the default) is used? The instructions do not state that is required. Instructions state that the units are shipped configured for horizontal duct attachment, implying that action is only needed to convert to downflow option.

  5. #5
    Join Date
    Aug 2011
    Posts
    10

    I think you guys are right - and the fix? Is a fix needed?

    My unit is configured for horizontal discharge as you surmised.

    I can now report more specifically that I feel a very small localized flow of cold air coming straight down from two areas along the opposite edges of the downflow panel cover. The installation manual talks about how these panels are attached like a knockout in an electrical box with "tabs" (Which are hidden from view from below as far as I can tell). I think this is a lot less air than I first thought, the back of my hand is very sensitive to even a small flow of cold air. Maybe the whole base including the covers is molded as one piece of plastic with very thin areas to enable knocking out the downflow base plates where my small leaks exist.

    Incidentally, I put my little mini temperature probe sensor in the leak air and it is 25 degrees cooler than the outdoor air (60 versus 85 F).

    The panels do not look cracked or loose, that was my original worry since the unit is new and just shipped. So I suspect that this is just how they are, not perfectly sealed, but not leaking enough to make much difference.

    I can reach under the base and easily put some silicone on the joint or (ask the installer to do so). After all there is only a half inch of water or so pressure involved so it will probably stop this small leak. I don't think it is necessary for the service people to open up the unit only to find that there is nothing wrong but I am really curious as to what exactly is going on there.

    All my observations are from peering and feeling through the small openings on the metal base frame so its kind of hard to see and feel.

    Obviously it would be best to seal them from the inside where the positive pressure is, but I am not convinced this is going to be necessary.

    What do you think about this? Is a small leak to be expected? Do you know how this panel seal is done at the factory? Are the install techs supposed to glue it in place if horizontal flow (the default) is used? The instructions do not state that is required. Instructions state that the units are shipped configured for horizontal duct attachment, implying that action is only needed to convert to downflow option.

  6. #6
    Join Date
    Apr 2009
    Location
    San Diego
    Posts
    75
    In California you have to have a title 24 test done after a new unit is installed. You new system has to have less than 15% air leakage. Maybe your contractor will be doing this test and sealing up the leaks when he comes back. Where do you live?

  7. #7
    Join Date
    Aug 2011
    Posts
    10

    Alabama, I'm in Alabama

    Alabama HVAC licensing requirements

    1. Hold an apprentice registration for 2 years or more, OR complete 3000 hours of coursework and experience, OR graduate from an approved HVAC Trade School.
    2. Submit an Examination Application to State of Alabama including $150.00 fee along with:

    • Affidavits that are signed and notarized by the employer(s) swearing that the applicant has worked in the HVAC industry for at least two years within the past five years, and all corresponding W-2 Forms from the employer(s); and/or
    •Copies of certificates showing that the applicant has attended at least 3000 hours of Heating and Air Conditioning educational training;
    •Or proof of graduation from an approved HVAC curriculum.
    3. The test is administered by computer at one of four PSI testing sites in Alabama. The exam is open book covering building code and industry practices.You must answer 53 of the 80 questions correctly for a passing 66.25%. You will be notified of pass/fail at the end of the exam. You have 4 hours for the exam.

    4. After passing the exam, you must furnish a fifteen thousand dollar bond to the state.

  8. #8
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,901
    i would get the installers back to seal it up im sure you paid some good coin for that unit ,they should have checked it before they left

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