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  1. #1
    Join Date
    Aug 2006
    Posts
    2
    Hello there. I just had a new 2 1/2 ton Westinghouse unit installed in my home. It replaced a similar type unit which functioned well for 21 years. The problem I am having is that the unit sweats on the outside and inside on the circuit panel. No one seems to know how to fix this. This is what has been done to date.
    1) Seal around the plenum in the attic. Did not work
    2) Remove insulation around the plenum in the attic. Did not work.
    3) Checked to make sure there was not too much refrigerant
    4) Company performed many other checks with gauges etc that appear to show the equipment in good working order.

    All parties involved know that the sweating is bad, especially on the inside of the unit but I have no answers on what to try next. The dealer where the installer purchased the unit from suggested that I install a vapor barrier in the attic and this will fix it. I hate to spend more money if I'm not sure this will resolve the problem. Any insight anyone can provide will be greatly appreciated.

    Many thanks,
    John

  2. #2
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Sounds like you had a larger system installed on the old duct system.
    This likely caused higher static(resistance to air flow),which has caused the air flow to drop below the required amoount,which makes the coil colder causig sweating.

    Westinghouse(Nordyne0,has some builder model air handlers that lower static capability ,then you old unit may have ,this could be part of the problem as well.


    Test the temperature of the air going into and coming out of the air handler,if it's over 20F(please post results),ducts maybe the problem.

    It may also be on low speed fan and need to be set on high,depending on the static.Static should be tested by your installer,post results here if they know how to test..


  3. #3
    Join Date
    Jul 2006
    Location
    Lancaster,Ohio
    Posts
    464
    Dash makes a good point, and may be right: I had a simular situation once and the final solution was this; I pulled the heat exchanger out of the furnace and had to re-glue the inside casing insulation. and found that there was a piece 26" x 40" was missing. And it solved that problem. But by the time I got to that point, I had re-insulated the complete trunk line and return and even the complete furnace. Including the drain pipe. Nothing worked.
    IcyFlame

  4. #4
    Join Date
    Dec 2004
    Location
    Brooklyn, New York
    Posts
    170
    Here's stupid question. Bear with me here. Does the unit have a p trap? Maybe your negative pressure in inproper drain is causing splashing water inside cabinet, which will cause u a whole lot of problems like- mold, electrical shorts..etc etc etc... ????

  5. #5
    check for proper ventalation in attic, very important. All duct in attic including blower compartment and plenum should be insulted

  6. #6
    Join Date
    Aug 2006
    Posts
    2
    Thanks for all the info so far. I am waiting to get the numbers back from my AC guy. I did make more changes over the weekend to no avail.

    1) Changed the fan speed on the motor to high. He thought that because I had it on low/med it could cause the cold air to not move "fast" enough out of the unit. Please note that this was the motor speed on the blower itself.

    2) Seal the top of the plenum in the attic and drill a 2" hole in the plenum and in the return air. His thought process was to cool the air where the unit was in hopes of stopping the sweating.

    Neither did not work.

    Another question: There seems to be an overflow pan in this unit that is sandwiched next to the blower. It does not cover it but I was wondering if this should come out since the unit is vertical and therefore not used?

    My last effort will be to add another duct allow more air to move out. Hopefully this solves the problem. If not, I will call the mfg. and see what they have to say about it.

    Thanks again,
    John

    [Edited by sloop on 08-28-2006 at 12:42 AM]

  7. #7
    Join Date
    Jul 2006
    Location
    Lancaster,Ohio
    Posts
    464
    [QUOTE]Originally posted by sloop
    [B] 2) Seal the top of the plenum in the attic and drill a 2" hole in the plenum and in the return air. His thought process was to cool the air where the unit was in hopes of stopping the sweating.

    >>>>>Everything that is in the attic must be insulated. You can not over insulate it.
    This is the clue...All parties involved know that the sweating is bad, (((especially on the inside of the unit)))

    They are right that there needs to be a vapor barrier...But why in the attic? Is it not insulated? Didn't your old unit work well for 21 years? Between where it is cold and where it is hot must be insulated. If not where the two meets will sweat. What is behind the inside of the control box? COLD! What is on the outside of the control box? HOT Question: Do you have good air movement inside the control area of the furnace? Maybe not...

    ((but I have no answers on what to try next. The dealer where the installer purchased the unit from suggested that I install a vapor barrier in the attic and this will fix it.)) Oh Didn't he also say that the two 2" holes was going to do something?

    Neither did not work.

    Another question: There seems to be an overflow pan in this unit that is sandwiched next to the blower. It does not cover it but I was wondering if this should come out since the unit is vertical and therefore not used?
    NO..Could be one piece.

    John You really ought to re-read my last post. That was truly a painful lesson. It was all done in the attic.

    My last effort will be to add another duct allow more air to move out. Hopefully this solves the problem. If not, I will call the mfg. and see what they have to say about it.

    IcyFlame

  8. #8
    Join Date
    Nov 2000
    Location
    Waco, Texas, USA
    Posts
    6,153
    Sloop you are keeping your house too cold.
    "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.

  9. #9
    Join Date
    Jul 2006
    Posts
    1,091
    so I take it.... the air handling unit is in conditioned space.

  10. #10

    Confused Indoor AC unit is sweating

    I am new to this site and have been reading the discussiions similar to my recent problem of indoor air handler sweating. I recently had major work done on the outside AC system with new fan motor and capacitors and to my knowledge this unit has not sweat like this before.
    From what I read it might be that the closet that the indoor unit sits in is somewhat open to the attic space and it should not, i.e., it should be well insulated around the plenums leaving the unit, correct?

    And I read where maybe the speed of the fan blower inside unit may not be at its highest speed?

    I would appreciate feedback about the sweating and coils icing up around the bottom where the drain pan and p trap are located. It is only in the early morning and is dried out somewhat by afteroon/evening and might just be the excessive humidity and 100+temps here in Texas. But the system is 12 years old and I can't recall sweating like this, and, the wood base it sits on show just recent water marks.

    Thanks

  11. #11
    Join Date
    Nov 2000
    Location
    Waco, Texas, USA
    Posts
    6,153
    Hi Boatdriver, I just did a service call yesterday of the same symptoms here in Texas. Conditions are super humid evidentally.
    "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.

  12. #12
    Join Date
    Nov 2000
    Location
    Waco, Texas, USA
    Posts
    6,153
    @ Boatdriver - your outdoor repair on the fan won't have anything to do with indoor sweating unless they also adusted refrigerant charge.

    Too hot up against too cold = sweat. Solution is to warm up the air flow inside the unit and decrease the heat of the air around the outside of the unit. This can be accomplished in many ways.
    "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.

  13. #13

    AC unit sweating

    Thanks Steve,
    It does not make sense that it only occurs when the house is coolest overall in the early morning and dries out by mid afternoon and its 100+ outside and 120+ in the attic.
    So, should I insulate and completely close off any air coming in around the unit from the attic, as I can see daylight above the unit around the plenums.

    I don't think that he added more freon or I would have been charged that, but I wll ask. I just did not want another trip charge for this, and it sounds like I can DIY myself.

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