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  1. #1

    Confused Evaporator coil condensation problem


    I have a Goodman H24F evaporator coil installed in the attic. It has both a primary drain pan, internal to the unit, and a secondary drain pan installed under the unit. The problem I have, for quite some time now, is that the secondary pan is constantly filling and draining through the secondary drain line. I am not sure what's causing the secondary pan's accumulation. I'd appreciate any help.

    Some more information:

    a. The primary drain line has been tested clean (water flows through it freely, it's not clogged).

    b. The primary drain pan is brand new. It was replaced on the suspicion that the old one may have been cracked, but that prooved not to be the case.

    c. The metal sheet underneath the primary pan is constantly wet. It is through this that the water drips to the secondary pan.

    d. All internal side panels appear dry. Again the only wetness is on the bottom panel under the primary drain pan.

    I am not sure how clean the coil is. The unit is 12 years old.


  2. #2
    Join Date
    Jul 2001
    Check for airflow at the filters first..... If clean call a service tech to check it out, the coil being dirty is one very common cause of sweating, there also could be a hole in the primary pan..... which you would not be able to see. Especially if its so much water it is getting out the secondary drain line. Then is the unit level and pan properly installed?

  3. #3
    Hi Wj,

    thanks for the reply.

    The filters are clean and there is airflow. As best as I can tell the pan and the unit are properly installed. There is no hole in the primary pan (it's new), and the old one didn't have any either (I filled it with water and let it sit for a few hrs with a piece of paper under it; nothing came out).

    I can access the coil by opening up the unit that houses it. I am inclined to clean it in place (can't disconnect the lines to remove it). Is that a good idea? What should I use to clean it?


  4. #4
    Join Date
    Jul 2007
    Beautiful, Philadelphia, the City of Brotherly Love!
    The primary pan you speak of is inside the air handler under the coil, correct?
    The wet area is under this pan, correct?
    If so the insulation is wet, for what ever reason, this will in effect make the insulation worthless, condensation will form on the sheet metal bottom of the air handler until it is completely dried out. This can only be done by running the blower for maybe several days without the cooling system being on. You could get a partial head start on this drying process by vacuuming out the bulk of the water.

    You did not say if the drain was originally clogged, or the drain pan under the coil that was replaced had a hole in it. If the answer is no to both then, the water might have come from a coil freeze up, which would cause water to run over the ice and miss the pan.
    The coil may have defrosted before the tech came to see the problem, he would then have come to the wrong conclusion as to what the problem was.

    This why it is so important for the HO to tell the tech all the conditions that existed before he arrived. Changing the filter, or making other changes yourself then not mentioning this to the tech is what causes most misdiagnoses of the real original.

  5. #5
    Join Date
    Dec 2006
    New Jersey
    does this coil have a baffle under it? i had a problem with a coil awhile back. was never given a baffle for it. the coil went past the drain pan. as it ran water would drip off the coil and right onto the insulation. then find its way to the secondary drain.

  6. #6
    There is no baffle under the coil. In fact, the bottom series of fins gets soaked in the primary pan ... rust over time. I have two units, both by Goodman, and they both have the same design.

  7. #7
    Join Date
    Jul 2005
    Quote Originally Posted by acmech13 View Post
    does this coil have a baffle under it? i had a problem with a coil awhile back. was never given a baffle for it. the coil went past the drain pan. as it ran water would drip off the coil and right onto the insulation. then find its way to the secondary drain.

    lennox by chance
    once you think you've seen it all
    I would rather work for free than be look upon as a thief!!!!!

  8. #8

    I am a newbie HVAC guy i have the same issue you described my secondary pan was rotted out. I had just replaced it water always collects in the pan i also confirmed the line was clear. What was the fix for your system? My unit is 11 years old, I only own the place for the past 2 this has been the behavior i have observed since i been here.

    any help is greatly appreciated


  9. #9
    Join Date
    May 2011
    Spring City, Pennsylvania, United States
    i had the same problem with a lennox downflow. it never had the baffles installed, took me a few trips to finally figure it out. also you said this was horizontal install, is there a proper trap and vent on the condensate line, without it the line will act like a straw and the fan will draw air back through it and will not let the condensate drain.

  10. #10
    Join Date
    May 2011
    Had this problem before...previous contractor did not install trap in drain line so condensate backed up into pan, easy fix install a trap with an air vent....should have been done in the first place.

  11. #11
    Join Date
    Jan 2007
    N.E. Ok.
    I take it you have a gas furnace with h24 coil. Can you add that if so.

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