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Community and Q&A

Copper Heat Pump Line Insulation Tips

smtwenty | Posted in Mechanicals on

Recently I installed a multi-zone LG heat pump at my home. I decided to run the lines inside the walls for a cleaner install once all was complete. The overall process went rather smoothly besides cutting the pre-installed insulation around some of the lines too short while making the connection at the wall-hung units. (See images for exposed copper in need of insulation)

At this point, my problem is getting additional insulation to adhere to the cut ends that are just exposed from the wall and at an extra angle. I have tried a handful of adhesives to try and get a new piece of PE foam pipe insulation to stick however nothing seems to hold. Because of that, I am now thinking about different methods.

My next thought is to use some expansion spray insulation in this area with a mold around the pipes to try and keep things as neat as possible. I need a product that will be safe for the copper while curing and once the system is running during both heating/cooling modes. What product would be best for this type of job?

Any alternate suggestions are welcomed.

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  1. user-5946022 | | #1

    It looks like the insulation on the left is individual insulation wrap around each pipe, then no insulation, then on the right it switches to a single piece of insulation around both pipes.

    It also looks like this is an indoor location not subject to the sunshine/UV breakdown.

    I'd be inclined to use rubber pipe insulation from the big box store. It is slit and self seals.

  2. Expert Member
    BILL WICHERS | | #2

    You can also get foam PE insulation that has a pre-applied adhesive strip on the cut edge.

    What I would probably do is slide some insulation on the pipe and then secure it either with some of the good quality electrical tape (scotch 35) in the color you want (white is an option, as is gray), and wrap the insulation with the tape to hold it in place. If you're careful, you can do a very neat job this way. If you can't get in there with tape, I'd use some zip ties or lacing tape. Lacing tape would be my preference over zip ties, but since you'd probably have to buy an entire roll for your small project so it might not be very economical here.


    1. smtwenty | | #3

      Thanks for your reply Bill. I had originally thought about more PE insulation however my main thought here was not being able to get a good seal on the end joints between the new PE and what is already on the pipe.

      If I can't get tape around the end joints (specifically for the side that enters the wall) what would your thought be on getting a seal here?

      1. Expert Member
        BILL WICHERS | | #4

        You don't need a perfect seal, so don't worry too much if you can't get everything perfect. In visible spots, the aesthetics are probably more important anyway. I would try with tape, probably by sliding a piece behind the insulation and then pulling the ends towards the front to wrap the insulation. Try to get it on the old and new insulation ends so that you can use the tape to pull things tightly together. I'd cut the new piece of insulation a little long too, so that it will want to push against the old insulation with spring force. You'll probably have to play with it a little, but you should be able to get a pretty good fit if you're careful.


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