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  1. #1
    Join Date
    Jun 2004
    Posts
    1

    Question

    I live in a new house with a new 5 ton Trane 12 seer elect. heating and a/c unit. The inside a/c unit located in the garage keeps leaking water although the drain line is clear. The inside of the unit appears to be sweating profusely. The A/C co. has been out numerous times and keeps insulating everything, including the cover plates and any gaps in the unit and has also replaced the coil unit, however, the problem persists. The upper inside plate when removed is covered in condensation and the copper tubing exiting the inside unit also is condensing and leaking down the outside of the unit. The A/C co. seems unable to find the problem and I'm not sure what steps I should take to insure that the problem is fixed properly. They keep coming out and putting more insulation on everything and saying that the unit is running fine....however, I still have a water problem, and I'm concerned about mold. The year warranty on labor and parts will be up soon and the problem remains unsolved. Any advice?

  2. #2
    Join Date
    Mar 2004
    Location
    Grottoes VA
    Posts
    5,856
    I have a customer with the same excact problem. I know the humidity in the garage is really high and suspect that is the culprit. The cure would be to increase ventalition in the garage, but not sure how to go about doing this. I guess I'm curiuos as to what the solution would be.
    Karst means cave. So, I search for caves.

  3. #3
    I have a customer whose airhandler is in a basement. There are no duct connections in the basement and the condensation formed on every exposed part of the system including the flex duct! I checked humidity, it was 89%, the humidity outside was 77%. They were running the dryer unvented using a lint catcher! I told them that it was necessary to vent the dryer, but do not know if they did.

  4. #4
    Join Date
    Mar 2004
    Location
    Grottoes VA
    Posts
    5,856
    My unit is the same way. But it is in a crawl space. My sump pump cycles every 5 min. I'm too busy to increase the insul. on the duct work. It would be too expesive to correct the moisture problem.
    Karst means cave. So, I search for caves.

  5. #5
    take a thermometer and check to see how much temperture drop your getting across your evap coil. take temperture of return air then supply air and if that split is greater than 20 degrees then you are not moving enough air across the coil. also make sure company has not overcharged unit or oversized condenser with evap being smaller. is your unit the proper size for your home, if it is to large then it can,t run long enough to remove enough moisture.
    also try having company install txv instead of the fixed orfice on your evap coil.
    lastly make sure you have enough return air, not enough return air will cause lower airflow across coil and drop pressure and temperture.

  6. #6
    Join Date
    Oct 2003
    Location
    UTAH
    Posts
    145
    sounds like a humidity problem in the garage. install a bathroom vent fan and wire it up to a humidistat.

  7. #7
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,432
    Originally posted by karsthuntr
    I have a customer with the same excact problem. I know the humidity in the garage is really high and suspect that is the culprit. The cure would be to increase ventalition in the garage, but not sure how to go about doing this. I guess I'm curiuos as to what the solution would be.
    Garage, attic, basement, and crawlspace locations are a similar problem. Its a dew point issue. The dew point temperature of the air contacting the cool surface is above the surface temperature, condensation. Any insulation that does not have a perfect vapor barrier on the wet side of the insulation will allow condensation on the cool surface. Solutions: reduce the dew point of the air on the cool surface or warm the surface. Ventilation introduces more wet air. Ventilation is not a solution to this problem! If insulation with the vapor barrier on the warm side impossible, consider dehumidification. Basements and crawlspaces for sure because mold control is necessary in these spaces. Crwalspaces need plastic ground cover and closed vents. For tough attics, close vents and dehumidify.

    Using a/c for humidity control requires the coldest coil possible for low load conditions. If supplemental dehumidification is used, warmer a/c coil temperatures are possible. Higher coil temperatures = warmer duct surfaces = less sweating = more btus per watt. Seems tobe a trade-off.

  8. #8
    Join Date
    Apr 2004
    Posts
    201
    I'm with teddy bear. The key word is barrier. Keep the warm moist air off the cold surfaces.
    ...SHEEESH!!!

  9. #9
    Join Date
    May 2004
    Posts
    1,462
    [Garage, attic, basement, and crawlspace locations are a similar problem. Its a dew point issue. The dew point temperature of the air contacting the cool surface is above the surface temperature, condensation. Any insulation that does not have a perfect vapor barrier on the wet side of the insulation will allow condensation on the cool surface. Solutions: reduce the dew point of the air on the cool surface or warm the surface. Ventilation introduces more wet air. Ventilation is not a solution to this problem! If insulation with the vapor barrier on the warm side impossible, consider dehumidification. Basements and crawlspaces for sure because mold control is necessary in these spaces. Crwalspaces need plastic ground cover and closed vents. For tough attics, close vents and dehumidify.

    Using a/c for humidity control requires the coldest coil possible for low load conditions. If supplemental dehumidification is used, warmer a/c coil temperatures are possible. Higher coil temperatures = warmer duct surfaces = less sweating = more btus per watt. Seems tobe a trade-off. [/B][/QUOTE]

    Well said and very correct!
    If all else fails....Try reading the directions!

    Tell it like it is and let the chips fall where they may.

    Any views or opinions stated here are strictly my own.


  10. #10
    Join Date
    Apr 2002
    Location
    Texas
    Posts
    165
    I think the possiblity of an improperly installed condensate waste line, without a "P" trap, is too great to ignore.

    Clues: Electric unit; inside of the unit is sweating; the upper inside plate (upper access panel?) is covered with condensation when it's removed; installing contractor has returned many times and applied additional insulation (Trane knew where the unit was sold, so it should need no additional insulation).

    Frank

  11. #11
    Join Date
    Aug 2003
    Posts
    82
    have the contractor check the charge
    if there is a overcharge the unit will sweat to much
    set the superheat to 15 and that may fix the problem.
    see this all the time with new installs.

  12. #12
    hey teddy bear..hope to see you at comfortech..as much as i know about humidity removal..i wish i was a fly on your wall for about two weeks so i could lean more...there is always so much more to every problem than we realize

  13. #13
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,432
    Originally posted by airman1
    hey teddy bear..hope to see you at comfortech..as much as i know about humidity removal..i wish i was a fly on your wall for about two weeks so i could lean more...there is always so much more to every problem than we realize
    Coming from you, I consider that a real compliment! Yes, I am looking forward to seeing you at Comfort Tech in St. Louis. It might be fun to have a little "HVAC-Talk" get-to-gether to put poster's names with faces.
    I appreciate your support. I like your concepts of having enough cooling capacity to maintain a 75^F setpoint on a really hot day with a few friends over. Love the discusion of "oversizing" as an excuse for not controlling humidity during wet cool weather. Nobody is right all the time including you and me, just kidding.

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