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Copper Pipe VS Large Diameter PEX for distribution system

Simply Rad
Simply Rad Member Posts: 169
I have been using a 2 pipe direct return distribution system for a very long time. I have been using PAP tubing up to 1" then I have to go to copper to accept the larger flow rates. Understand I mainly install RF for large custom homes( 10K + fts). I am wondering how big of challenge it is to work with 1 1/4"- 2" PEX tubing in tight installs....though most of the time I have drop ceiling to work with. Also, I have been insulating my main lines to not only help system performance but also isolate the tubing from potential noises. I have included a project I designed and installed last year as an example. Thanks for you input. Jeffrey
Jeffrey Campbell


    EBEBRATT-Ed Member Posts: 11,989
    Not a pex expert but the larger sizes are difficult to work with. I would think your better off with copper in most cases you can't bend the pex the way you would think or use a lot of pex fittings.

    As far as insulating pex this is a question I have been looking for input on myself.

    If you bend the pex your only choice is armaflex. Un fortunately it isn't made in sizes to fix pex snugley. Ok for heat maybe.

    We used it on chilled water and had a condensation mess
  • Paul Pollets
    Paul Pollets Member Posts: 3,508
    edited January 2017
    I use Viega PureFlow PEX for larger distribution piping larger than 1". It comes in straight lengths and their press fittings (and pipe) are less expensive than copper.
  • Simply Rad
    Simply Rad Member Posts: 169
    Paul Thanks for the option. I think Viega is a great company with lots of innovative options. I have never used them because I install mostly new homes with Warmboard and Fosta Pex OD is to large for the groove. For years I have been using Watts PAP for the WB and distribution.

    EBEBRATT-Ed I have used Armaflex for chilled water supply lines and have not had any condensation problems. I normally used PAP style of tubing and yes its not the same OD the insulation is sized for.
    Jeffrey Campbell
  • Simply Rad
    Simply Rad Member Posts: 169
    Also, Watts has large diameter PEX in 20,100 and 300' rolls
    I really try to use as little fittings as possible and I was curious how hard it is to work with up to 2" PEX , especially bends. I have used 2" HDPE on Geo loop fields and that would never work inside unless you use alot of fittings.....just comparing larger diameter tubing. I know it would work with fittings. I have actually looked at Aquatherm which is alot like HDPE. I have the fusion equipment also. I just have heard its hard to work over your head with the Fushion equipment. With Geo loop fields its all done on the ground. But Fusion(pun intended) provides a superior joint. Jeffrey
    Jeffrey Campbell
    EBEBRATT-Ed Member Posts: 11,989
    Used a lot of aquatherm. Great product except:

    needs a lot of hangers
    up to 2" is ok
    over 2" is adifferent story with regard to the tools
    mucho $$$$$$$$

    But the stuff is as tough as it gets

    We had a glycol system done with it 2" risers and the hangers fell off outdoors in the winter. The risers were twisted 180 degrees and didn't break