pex insulate/water hammer?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by pitteach, Feb 21, 2008.

  1. pitteach

    pitteach New Member

    Messages:
    27
    Location:
    Hamburg, NY
    I'm running pex to a new upstairs bathroom. I'm hearing mixed things on this so I want to be sure.
    Do I need to insulate the hot runs to prevent heat loss?
    And do I need arrestors at the fixtures (including laundry) or will proper securing do the trick?

    Also, what is the best way to stub out to the fixtures? Should convert pex to copper below the floor, or go pex as far as I can go ?

    [​IMG]
    Last edited by a moderator: Feb 21, 2008
  2. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    Arrestors needed.
    Insulation per your local energy code.
  3. run the pex as far as you can

    you can run the pex all the way up to
    the stops if you so wish.....keeps less
    joints in the walls that way...


    ideally it would be nice to insualte the hot line.....
    I dont think it is done much by plumbers, only DIY folks....


    with the pex you can easily put air hammer --chambers
    anywhere you want to in the lines ......
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,153
    Location:
    New England
    The arrestors should go on the washing machine. If you don't want to pipe them in, both Watts and Sioux City make them with hose connectors on them that go in-line with the washing machine hoses...they add about $1-2 to the cost over a solder or screw in version. I think HD carries the one brand, and Lowes the other.

    Finding shutoffs for the pex (actually, they are often the same as for copper) is a little tougher - you need the ss insert to reinforce it so you have something to compress against. I like the transition to copper if it is a valve you are going to use often (unless something like a washing machine box with integrated valve that can be screwed down), as it feels better with the solid copper rather than the slight flex you get with only the pex. If it is something that gets turned off only for maintenance some years down the road, probably not a big deal.
  5. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    Just make sure you use all zurn brass fittings just like MP Mark ;):D
  6. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH

    Isn't that the brand that fails/failed?
  7. Herk

    Herk Plumber

    Messages:
    547
    Location:
    S.E. Idaho
    I've never actually seen a PEX or PB water system with water hammer. Plastic has a cushion. (After you shut off the water, you'll see a slow pressure drop as you release the water.) As to insulation - I don't know how practical that would be. Sure, it will hold heat in the lines a bit longer. If it's a short line, I wouldn't bother. PEX holds heat a bit longer than metal pipe anyway.

    If it's a longer line, having it insulated means you'll get warm water before you get hot water. If you're energy conscious, it wouldn't hurt.
  8. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    For stub outs you can use one of these brackets nailed across the studs.

    [​IMG]

    Then connect the pex to one of these stub outs and solder it to the bracket above.

    [​IMG]

    Or, you can as stated above run pex direct to the stop valve. You can also put a chrome sleeve over the PEX to make it look purdy...

    [​IMG]

    Pex has very little heat loss Which is why in radiant heating applications it is encased in aluminum radiators to work. You can insulate if desired.

    Pex is also resistant to water hammer but yes at the washer box I would install one with arrestors.
  9. pitteach

    pitteach New Member

    Messages:
    27
    Location:
    Hamburg, NY
    I'm going with the Sioux Chief Ox Box for the laundry. It comes fully loaded with arrestors and direct pex hookups and it is USA made (hard to find!). Everything is compact and flexible for install which is what I need for a closet setup.

    I'm going to try and hookup everything else directly to pex. I was concerned about the look at the toilet supply, but I like the idea of covering it with the decorative tubing.

    One more question: How concerned should I be about leaks in the laundry closet. What kind of supply lines? What about auto shutoffs? I'm going to install a small floor drain just in case. (This is on the second floor.)


    [​IMG]
  10. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    The OX Box is a great choice!

    I would use Braided Stainless Steel "No Burst" supply lines for the washer. I would not recommend the "Floodsafe" connectors as :
    1 The FloodSafe Valve is protecting a hose which will not burst.
    2 They are prone to "False Trips" which require disconnecting the hose to reset.
    3 I have seen them break between the connection to the supply and the "Floodsafe" valve resulting in a flood.

    [​IMG]
    Last edited by a moderator: Jun 4, 2011
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,153
    Location:
    New England
    You may want to consider a pan for the washing machine, plumb its drain to the floor drain.
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