Using soft copper in a crawlspace for heat pump water heater

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Christian Kohler, Nov 5, 2020.

  1. Christian Kohler

    Christian Kohler New Member

    Joined:
    Nov 5, 2020
    Location:
    Oakland, California
    Hi,

    I'm planning to install a Sanden Heat Pump Water Heater. These heat pumps do not have a tank, so I have to run about 20 ft of supply and return water line through a crawlspace from the outdoor unit to a laundry room where I'm planning to install a 120 gallon tank. The crawlspace is fairly shallow, and is only accessible from a small access hatch in the floor. I would like to use copper instead of PEX because I prefer to not have domestic hot water (could be up to 175F) run through plastic pipes. The manufacturer requires 1/2" pipes.

    Given the small access hatch, it will be difficult to get 10 ft lengths of copper pipe into the crawlspace and make sweat connections in there. Would it be acceptable to use soft (annealed) type L copper coils for this 20 ft run in a crawlspace? Does soft copper have to be protected, or can it be hung from the floor joists, and wrapped in 1 1/2" foam pipe insulation? This way I could have one continuous run in the crawlspace and make all connections above the crawlspace.

    Thanks
     
  2. wwhitney

    wwhitney Well-Known Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    Your pipe has to exit the crawl space at some point, so couldn't you drill your exit hole and feed in the straight 10' (or 20') length(s) from the outside? How many fittings would you need in the crawl space?

    Cheers, Wayne
     
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  4. Christian Kohler

    Christian Kohler New Member

    Joined:
    Nov 5, 2020
    Location:
    Oakland, California
    Wayne,
    Thanks, that is a good suggestion. Unfortunately there is a fence about <6 ft away from where it comes outside. So I could use 6 ft pieces at most. I have to make a 90 degree horizontal turn, which I would prefer to do with 2 45's, and then I have to have another 90 to come up through the floor. I think that makes about 8 connections (since I have supply and return pipes).
     
  5. Reach4

    Reach4 Well-Known Member

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    Sep 25, 2013
    Location:
    IL
  6. wwhitney

    wwhitney Well-Known Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    No crawl space vents anywhere that you could temporarily remove?

    You could always drill a hole in the fence. : - ) Although I bet there's another house on the other side.

    I know soft copper is a bit of a pain to work with, it's not like PEX at all. What I don't have the experience to know is which would be a bigger hassle--dealing with the soft copper or dealing with soldering in the crawl space.

    Cheers, Wayne
     
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  7. Jeff H Young

    Jeff H Young In the Trades

    Joined:
    Feb 27, 2020
    Location:
    92346
    Soft copper will work , maybe not prefered but we used to use tons of it plumbing homes. hard copper should be hung every 6 foot or less so soft should be at least that well hung do what you can get 3 or 4 hangars on it insulated as well youll be ok!
     
  8. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Soft copper should be easy enough to deal with. Compression fittings are a good alternative to soldering, although I was thinking the thought was that the soft copper could eliminate the need for awkward connections.
     
  9. Jeff H Young

    Jeff H Young In the Trades

    Joined:
    Feb 27, 2020
    Location:
    92346
    a lot of suggestions either way you do it be fine . i was thinking same thing drill a hole in fence knock the board off then nail it back on , whatever easy peasy job!
     
  10. Christian Kohler

    Christian Kohler New Member

    Joined:
    Nov 5, 2020
    Location:
    Oakland, California
    Thanks for all your feedback. I'll take a look at feeding it through the fence. It does seem a bit of a pain to straighten out the soft copper coil in the crawlspace. I could imagine it might end up quite wavy. But it is good to know it is an option.
     
    Jeff H Young likes this.
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