Gray colored Plumbing in Mobile Homes? Is it PEX, Qest, Polybutylene? What fittings?

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by rchii, Jul 31, 2008.

  1. rchii

    rchii New Member

    Messages:
    1
    I am doing some repeirs on a mobile home and the plumbing is the gray colored flexible type. I have been trying to learn more about this stuff. It is my understanding that the gray color indicates it is the older Qest brand that Shell stopped making. I need to kow more about what fittings work. I am getting the impression that Polybutylene(PB) fittings can be used with the correct crimp rings. Can 'Flare-it' fittings be used with this gray stuff? Are the gray colored 'nuts' I see advertised online the right things to convert to pipe thred fittings? I realize I am asking alot of questions, I just don't want to start buying pieces that won't work. I am looking to use conversion/adapter fittings to switch to the newer PEX tubing. Can anyone help?

    Thanks!
    Bob
  2. nhmaster

    nhmaster Master Plumber

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    Copper fittings and copper rings are the best thing to use. That being said, you are eventually going to have to replace it all when leaks start popping up. What you have is Polybutylene piping and sorry to say, it's crap.
  3. jimbo

    jimbo Plumber

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    Gray is polybutylene. PEX is either milky, or red. or blue. or red/blue striped.
  4. Redwood

    Redwood Master Plumber

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    I usually use Sharkbites Connectors to transition from Polybutylene to another material.
  5. hj

    hj Moderator & Master Plumber Staff Member

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    Pb

    There are special rings to use on PB with PEX crimp fittings.
  6. nhmaster

    nhmaster Master Plumber

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    You are just kidding right?
  7. Redwood

    Redwood Master Plumber

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    Absolutely not!

    If you are making a repair on a trailer I'm cutting under the trailer and transitioning there, then anything from there to above will be PEX.

    I would consider the Sharkbite to be better than the crimp rings. Isn't that where Polybutylene has most of its problems?

    Ideally there would be a complete repipe but that doesn't often happen on a tin house on wheels budget.
  8. nhmaster

    nhmaster Master Plumber

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    Actually most pb failures were due to UV light degradation of the pipe itself. The other major failure was acetyl fittings along with aluminum rings. The pipe expands and contracts quite a bit with temperature change and causes the fittings to stress and break. I transition to pex with a pb x pex coupling and always use the copper rings. No problems in well got to be 15 years now. Can't say that I'm a fan of sharkbites for anything other than temporary repair or testing. I have a problem with that rubber O ring thing. Maybe it's just me, but have you ever flexed one of those with the pressure on. They leak.
  9. Redwood

    Redwood Master Plumber

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    I have never had a problem with a sharkbite leaking even when flexed. If you have experienced that then you need to insert the pipe further. Sharkbites are approved in concealed locations and underground.

    As for O-Rings I assume that you also have reservations about Pro-Press, Sloan Valves and a few other things in plumbing that use O-Rings.

    I always assumed that the Polybutylene failures were related to Chlorine not UV.
    http://www.pbpipe.com/Eligibility/EligibleSystems/tabid/68/Default.aspx
    Last edited: Aug 1, 2008
  10. nhmaster

    nhmaster Master Plumber

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    Yes they are approved, but then so are aav's. As for pro-press I guess I'm still on the fence. I have one and use it often for exposed piping in commercial applications, but I guess I still don't feel real confident about burying a joint. I don't want you to get the impression that I'm against anything new. I was the first company in the area to install pex. But I've done a lot of research on the web regarding O ring type connections and I get a lot of different opinions. And I have used both the sharkbites and watts connections and I can make both of them leak if I flex the pipe just right. Would that happen in normal use? I dunno. By the way Victaulic has introduced a new propress compatible steel fitting. The rep left me a box o them to try.
  11. Redwood

    Redwood Master Plumber

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    AAV's??? No reason to start cussing!:mad: LOL
    I would not use the Watts Qwik Connectors...
    Have never seen the problem you describe with a Sharkbite!
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    They sell an end reamer tool for use with Sharkbite fittings that's a good idea to use. It puts a nice smooth microbevel on the end of the pipe. If you had a leak, IMHO, the end of the pipe damaged the O-ring on the way in.
  13. Herk

    Herk Plumber

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    I have never seen any indication that Sharkbites are approved for use with polybutylene. They are for use with copper, CPVC, and PEX. The problem, as I see it, is that the inside diameter of the PB pipe is larger than PEX. The outside diameters are the same. So the little plastic insert that is designed to help keep the pipe from shrinking and slipping out is useless. (I remove them when used with copper.)

    PEX fittings cannot be used with polybutylene. There is a transition coupling that has both a PB and PEX end as well as two different crimp rings. Again, the wall thickness of the PEX crimp is heavier, and the thinner version of the copper ring is for PB. PEX rings are usually colored black to tell the difference, while the copper rings for PB are plain copper.
  14. Redwood

    Redwood Master Plumber

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    And the guarantee for the PEX X Polybutylene transition fitting is?

    As far as Polybutylene the only guaranteed repair is a complete repipe!
    If the customer is unwilling to do that its a repair without a guarantee and they need a repipe.
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