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Condensation issue

pfletch | Posted in Energy, Heating & Insulation on January 30, 2012 02:26am

I live in the humid south and we have been renovation our house to be more energy efficient. We added a full length ridge vent to our roof when it was reshingled. When we replaced the HVAC units, the freon line started dripping condensation onto the living room ceiling. The HVAC guy came back and said that we needed to increase the insulation around the pipe. So we added additional insulation to the attic (according to his recommendation) and the problem has only gotten worse. Any ideas on fixing this? The freon line is already wrapped with self sealing rubber pipe insulation.

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  1. calvin | Jan 30, 2012 03:04pm | #1

    pfletch

    Are you sure it's condensation on the line?  Could it be the condensate drain leaking?  The pan under the unit's drain leaking?

    I assume the air handler is in the attic space?

    Assuming also that he ridge vent or the newly shingled roof isn't causing the problem either.

  2. User avater
    xxPaulCPxx | Jan 30, 2012 03:45pm | #2

    As long as it's just the freon line that's leaking - not the pan:

    Make a long retangular box out of rigid foam board, seal the seams with tape.  Once the intial water inside has condensed out it should stay dry.

  3. rdesigns | Jan 30, 2012 05:51pm | #3

    What kind of insulation was it that you added? Fiberglass?

    The reason I ask is because there are two things needed:  the isulation itself, plus a vapor barrier to keep the warm, moist air of the attic from coming in contact with the the cooler surface. Fiberglass would not provide such a vapor barrier.

    The recommendation of xxPaulCPxx would provide both if you can use such a box to follow any bends in the line. Otherwise, the added insulation needs to have an outer vapor barrier skin, like aluminum foil, and the skin needs to be sealed air tight as possible. 

  4. DanH | Jan 30, 2012 08:22pm | #4

    This suggests that the system may not be properly charged.  In particular, it may be a hair undercharged.  This is particularly likely if you're seeing condensation forming on the outside of the foam insulation.

    Another possibility is that a lot of humidity is getting into the attic from somewhere.  Make sure that any vent fans are vented outside, and the vent ductwork hasn't become disconnected.

    But, failing those, you need to keep humidity away from the line.  The line should be COMPLETELY covered with foam insulation, and all the joints should be taped or glued so that no air can get in.  Presumably the foam is split lengthwise, and you may need to glue the entire length of the split.

  5. oops | Jan 30, 2012 10:54pm | #5

    condensation issue

    You said the HVAC guy said one thing and it seems you did another. He said to add insulation around the pipe. He did not say to add more insulation to the attic. There is special insulation for insulating refer lines. Usually foam with a vapor barrier that fits over the lines. Not good enough to bury them in the fiberglass insulation.

    The HVAC guy should have insulated the lines. Make me wonder about him. Did he do this under a permit?.

    Also, did you did you have existing soffit vents or added them if you did not. A Ridge vent does not work properly without them. Even with gable vents which you probably had/have.

    1. pfletch | Jan 31, 2012 08:31am | #6

      The freon lines were previously insulated from the old unit. I'm not entirely sure what condition the insulation was in when he did the job. But I talked with him directly about the issue and did exactly what he told me to do with insulating the attic. Previously there was about 6-8" of blown-in insulation. Now there is around 16-20" of insulation which will make this job harder to fix. I will check with him about the freon levels.

      1. DanH | Jan 31, 2012 08:50am | #8

        If the lines haven't been changed, and you didn't have the condensation problem before, then you need to figure out what HAS changed.

        - Freon low?

        - Did he knock a bathroom vent duct loose?

        - Etc.

  6. pfletch | Jan 31, 2012 08:35am | #7

    Thanks for the ideas. I had considered some of them but wasn't entirely sure it would fix the issue or create a bigger issue. Once I get the HVAC guy back to check the freon levels, I will try a few of these ideas and see if any work. Thanks again guys.

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