I have a mini-split AC unit with a built-in condensation pump. This pipe is connected, but it goes down and up like a U. The manual says it must go upwards to prevent water from pooling in the pipe. Also, this pipe is leaking.

  1. What type of pipe is this?
  2. I need to reduce this pipe by 6 inches. How do I reconnect so it's water tight?
  3. What kind of tape should I use? I put on Flexseal tape but it didn't stick well.
  4. Can I pour in vinegar or something to cleanse the mold out?

More info: The AC unit is in a tight spot in the ceiling. It's hard to take a good picture. The drawing below is how my AC unit is positioned. The green line is how the drainage line is really connected. It's supposed to be hard PVC. The builder did it, not me. I know nothing about AC and plumbing.

Installation manual

AC condensation pipe

  • We need better pictures of the setup and the connections. you got everything covered.
    – JACK
    Jul 15 '21 at 18:51
  • Am I looking at a floor or a wall? What way is right-side up? That scotch tape doesn't exactly make me think of professionalism.
    – MonkeyZeus
    Jul 15 '21 at 19:27
  • It's not water tight now as it appears to be leaking.
    – jwh20
    Jul 15 '21 at 19:27
  • 1
    Get rid of the flex it is a mold generator and harder to seal because of the ridges, you do not want a low spot in the drain.
    – Ed Beal
    Jul 15 '21 at 20:22
  • 2
    It looks like 5/8" or 3'4" corrugated drain line. That's all we can tell from here. Can you twist the fitting upward and tie off the drain line from above?
    – JACK
    Jul 15 '21 at 20:23

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