I've got an old AC unit (probably 13+ years old) that came with the house that I bought. This summer I noticed some water damage on the drywall in the basement, so I cut the damaged drywall away, and found that the pipe coming from my AC unit to my furnace had a bunch of condensation on it that would collect and leak out onto the drywall.

It seems like the spot it's dripping from is the lowest point in the pipe (left and right of this point both bend up)

How safe is it to try and bend this pipe (which I'm assuming has freon in it?) so that it's more level?

Is there some other kind of insulation I can put on this to prevent the condensation. Right now its the standard foam tube that you wrap around.

3 Answers 3


Did the problem just start? Is the condensation on the pipe frozen? If so, this is an indication that the compressor is overworked (possibly low on coolant). If you are seeing any frost, you should turn off the system before the compressor burns out and call an HVAC professional.

Insulation is wrapped around the coolant line to prevent condensation from forming and causing damage. That insulation may have started to fail. If so, replacing it is an easy enough job.

I reccomend you turn off the system for a little while so the coolant line can warm up. Pull off as much of the old insulation as you can and wipe it down to remove any leftover condensation. Then replace it with the tightest-fitting and highest R-value insulation you can find.

When re-insulating, be sure to seal all of of the crevices. If the pipe insulation tubes have an open slit in the side, make sure you seal the slits with insulated tape. If any copper is exposed, it is a point for condensation to form. The coolant line should be completely covered from end to end.

I reccomend that you don't bend the pipe. The coolant pressure is somewhat higher than your generic water supply, and if you damage/crack the line, it won't be pretty.

  • After cutting off the damaged drywall, I'm thinking the problem has been happening for a couple years now, but has gotten progressively worse, and finally the water damaged started to show through the front of the drywall. The leak dripped onto a sloped part of the ceiling, and ran down the back of the wall, which is why it took a while to show. No frost or ice or anything like that. Just some oxidization on the copper pipes. Called an HVAC guy out to check freon levels, said they were ok. Commented Jul 21, 2011 at 19:19

Sounds like the insulation around the coolant pipe needs to be sealed better (if air can't get to it, you won't have any condensation). See this similar question: Corrosion on copper pipes due to insulation (with foam)

  • So if I re-insulate, and possibly run a dehumidifier, I should be ok? Commented Jul 20, 2011 at 23:45
  • 1
    The dehumidifier would only apply if the ceiling was always open, or if you had a damp basement. Just worry about the insulation and getting it well sealed.
    – BMitch
    Commented Jul 21, 2011 at 10:56

I had the exact same thing happen. In the attic rats had eaten away the rubber insulation. For some reason they love it. Water came through the ceiling into one of the bedrooms. An AC guy came out and said to replace the old insulation with new insulation from Lowes or Home Depot.

Total cost of the insulation: $15.

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