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Tube through wall for minisplit

Trevor Lambert | Posted in General Questions on

Another question regarding my minisplit DIY install. The tube they supplied to pass through the wall is about 6″ long, which is useless for me since the wall section I have is 17″ thick. The tube is 60mm ID, or 2.375″. This appears to be as small as it can be to easily slide the line set through. 2.5″ PVC pipe exists, but for some reason it doesn’t exist in Canada. So I’m left with two options.

1. Use 3″ PVC pipe. This looks friggin’ huge, but it’s cheap and easy.

2. Import a piece of 2.5″ pipe. This will cost me about $60, and set my install back 1-2 weeks. 

I’m I crazy to be concerned about putting an extra half inch diameter hole through the wall? I feel like maybe I am, but it’s hard to see from inside my own head.

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Replies

  1. Expert Member
    Zephyr7 | | #1

    It’s not a big deal to have a too-big sleeve since you’re going to want to stuff it with insulation and seal the ends (I like to use duct seal and/or fire sealant sheets, both of which are clay-like materials).

    You might try a commercial plumbing supply house. The commercial supply houses usually have a better selection of materials than the box stores do.

    Bill

  2. Nathan Scaglione | | #2

    Don't you guys use ABS up there? And no 2.5"? Weird... also check the electrical section for PVC conduit

    Main thing to watch with 3" is to make sure the indoor head will cover the hole, or you'll end up with an eye sore.

    Drain pipe is definitely the way to go, you can drill your hole at a slight downward angle, slide pipe through, mark exact and get a really good fit.

  3. Trevor Lambert | | #3

    No 2.5" ABS either, or electrical conduit. The commercial places generally don't sell to someone off the street in the best of times, let alone right now. I'll just go with 3". It's not a wall mount unit, so covering the hole isn't a factor. I wasn't planning on stuffing it with insulation originally, but may do so with the larger size tube.

    1. Expert Member
      Malcolm Taylor | | #4

      Trevor,

      I always oversize the sleeves I put in foundation or framed walls for services and then fill them with foam.

      1. Expert Member
        Zephyr7 | | #5

        +1 for putting in a bit bigger than you need. You’ll probably thank yourself for doing so years down the road when you have to change something.

        Bill

  4. Eric Whetzel | | #6

    As others have suggested, using the 3" PVC should be straightforward.

    In our case, I used ripped up bits of Rockwool Comfortboard 80, but the Rockwool batts would work as well, to fill gaps inside the PVC, along with the duct seal on the interior and exterior ends to air seal.

    You can see a series of photos here: https://kimchiandkraut.net/2019/03/06/hvac-part-2-of-2-ductless-mini-split/

    It's held up well with no issues.

  5. Jamie B | | #7

    3" PVC or ABS is fine. I get the worry about the extra ½ inch, and it might seem like a lot of wasted space on the inside of the pipe. But you'll probably find the extra room will give you an easier passthrough.

    From my personal experiences I now overcompensate pipe size for through wall sleeve like this.

    I've attached a not so great photo of a 3" x 20" sleeve I had to retrofit through a concrete foundation wall for a conduit. All the stuff I had to put through it fit in 3" but I never accounted for the bend resistance of the tubes, so it became a major pain to feed it through and not have it push beyond the drywall layer. Next time I'll default to 4" (and ideally it'll be thought of before concrete pour as well)

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