PEX connection question

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by timbob96, Aug 13, 2010.

  1. timbob96

    timbob96 New Member

    Messages:
    4
    Location:
    SW Missouri
    I had a leak in an older modular home. The black pex line had broken right where it connected to the shut off valve under a sink. The connection was made with a brass collar on the pex and then a compression nut. The pex broke right at the line side of the collar. The pex had no insert in it. I'm sure ALL the other connections in the home are done the same way. Should I be concerned about the others breaking too ?? Is it alright to connect pex in this manner. Thanks for your input.
  2. nhmaster3015

    nhmaster3015 Master Plumber

    Messages:
    836
    Location:
    The granite state
    I would be concerned yes. If they are all like that, they will need to be re-done
  3. Gary Slusser

    Gary Slusser That's all folks!

    I've never heard of or seen black PEX but, you don't break PEX or PE pipe.

    I suggest the pipe was pulled out of the fitting instead of being broken off.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,263
    Location:
    Cave Creek, Arizona
    The first thing I do when I see a customer with ANY type of plastic supply lines to their faucets, is suggest they remove ALL of them and replace them with the flexible stainless steel braided ones, PERIOD.
  5. timbob96

    timbob96 New Member

    Messages:
    4
    Location:
    SW Missouri
    the plastic is NOT going to the faucet...it's going into a cutoff valve....then, the flexible steel one goes from the cutoff valve to the faucet. Is connecting pex to the cutoff valve with the brass sleeve and compression nut an acceptable way to connect it....without the insert. That is my main concern....thanks
  6. timbob96

    timbob96 New Member

    Messages:
    4
    Location:
    SW Missouri
    definitely broke.....black pipe on both side of brass sleeve...
  7. Jerome2877

    Jerome2877 In the Trades

    Messages:
    397
    Location:
    BC
    I don't think its pex, it would probably be poly. The brass ferrule's are not meant for plastic pipe of any kind. They will eventually cut into the pipe and cause a leak, as you now know. I would replace all of them in the home by transitioning to pex then using pex shut offs.
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,814
    Location:
    New England
    Pex can be connected in a few ways: slipped over a barbed fitting then crimped, expanded (applies to Wirsbo only) then allowed to collapse over a custom barbed fitting (too big to slide over, it needs to be expanded first), or with a compression fitting (all of them I've seen use a stainless steel insert).

    Are you sure the pipe is pex? I've never seen it in black - doesn't mean it doesn't exist. What is the OD of the pipe? If it is 5/8", a compression shutoff should fit after you insert the ferrule insert to support it from collapsing when you try to tighten the compression nut. If it isn't 5/8", the compression ring won't fit properly to allow a good seal.

    Pex normally isn't brittle enough to fracture, which is why I question if it is pex. If it got extensive UV exposure, maybe, but glass absorbs most of it so it's hard to get that problem indoors.
  9. Fubar411

    Fubar411 New Member

    Messages:
    141
    Location:
    St Louis, MO
    Just a quick tangent question here... I replaced the plastic/braided supply lines with the chrome brass ones. It didn't take much time at all and looks so much better. Is there any downside to using those?
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,814
    Location:
    New England
    If you can identify the pipe properly, you might also be able to use a Sharkbite valve...that just pushes onto the end of the pipe. they only work on certain specific types of pipe.
  11. timbob96

    timbob96 New Member

    Messages:
    4
    Location:
    SW Missouri
    o.d. is 5/8.....but, i'm sure the other connections don't have the ferrule insert. as far as it being pex or not....it's an older modular home...the water lines are all the black pipe and are continuous runs except where there are t's....there are not elbows where it turns to go to other connections....there's just bends (not sharp)....on the original connections (like at the t's) there are those crimp style connectors like they use on pex.....again, may not be pex, but that's the best way i could describe it so everyone would know kinda what i was talking about. when i fixed the one leak, i stuck one of the sharkbite type connectors on the black pipe coming up thru the floor....then pushed a piece of 1/2 white pex into the other end of the sharkbite.....then, slipped a 5/8" brass sleeve onto the pex and connected it to the shut off valve with a compression nut....didn't use a ferrule insert/didn't have one.....it sealed fine, no leaking.....i'm just worried about, over time, the brass sleeve cutting into the NOW PEX LINE and leaking again in the future.....do you think it's "fine"...or as Jerome2877 states above, will i have more problems in the future and need to change it all out now??? thanks for your input..
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,814
    Location:
    New England
    Without the SS insert you are at severe risk of having the shutoff pop off at some inopportune time. If you add the SS ferrule, you should be fine. Brasscraft sells them in the box for their shutoffs specified for pex, but the actual shutoff isn't any different, it's all just the packaging. They also sell them separately, but you're unlikely to find them at a big box store.

    The reason for the ferrule is to give the compression fitting something rigid to compress against. As it is now, you're pressing against a soft, elastic piece of tubing...it needs to be firmed up with the ferrule insert!

    If you remember the SHarkbite, it had a piece that fit inside the pipe, so it would be rigid to ensure the connection remained good...you need the same thing with the compression fitting.
    Last edited: Aug 13, 2010
  13. Jerome2877

    Jerome2877 In the Trades

    Messages:
    397
    Location:
    BC
    I have seen this happen alot with or without the inserts. The problem is the brass edges dig into the plastic and over time will cause a leak. This is why when connecting the supplies to a sink with 3/8 pex you should use the plastic ferrules instead of the brass that is supplied with the compression shut off. I havn't seen a 1/2" plastic ferrule and don't know if they are even available as the proper way to do this would be to use the pex shut off.
    Last edited: Aug 13, 2010
  14. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,814
    Location:
    New England
    The ones that Brasscraft sell, SS, are quite long so the compression ring and valve itself have decent support. You need to support the valve. I wouldn't put a valve directly on pex if it wasn't supported well.
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