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PB Infloor Manifold replacement

JUGHNEJUGHNE Member Posts: 3,176
We have in-floor radiant in this house, the buried tubing is PBOX, ASTND-3309,SDR-11.  The polybutylene has O2 barrier and has not been a problem for the 22 years it has been in concrete.  The only issue has been the Infloor Maxxon manifolds (#2231).  The balancing valves are starting to leak at the knobs.  The 3 zone control packages (2082) have worked well.  (Nice compact unit).  I realize its time for new manifolds and sometime in the future changing the zone control (4-way mix valve & pump). No income from fixing your own stuff !!

But for now just manifolds.  I have found only one transition fitting available for the PB to PEX needed at new manifold.  Sharkbite #U4008 gets spendy when you need about 40 of them.  Would like a manifold ready to accept future mixing valve/pump.  Existing PB is 1/2" OD & tight 3/8" ID.  Any suggestions for manifold or optional transition fittings.  I realize that PB has had the lawyer curse put on it, but the O2 barrier must have been effective as this had a CI boiler with only basic air venting and copper pipe/steel piping until 2 years ago and nothing showed corrosion at the change out to mod con.  {I see that "Polybutylene" is not even in the spell-checker, must really be a dead horse.}

Thanks for any advice.


  • kcoppkcopp Member Posts: 2,748
    PB got a bad rap.....

    inch per inch is is actually stronger than Pex. Sioux chief actually still makes the PB fittings....

    You could use one of their manifolds and sweat in the PB adapters. just a suggestion.
  • JUGHNEJUGHNE Member Posts: 3,176

    Thanks for the reply kcpp, I did look at Sioux Chief and it's not clear that they have 3/8" PB/PEX fittings as they refer to 1/2" only. Also would have to invest in crimping tool.  I have plenty of the 3/8" PBOX left for additional projects.  You know one is never done with his own heating system. thanks.
  • RobGRobG Member Posts: 1,850

    How about compression fittings? Brass 1/2 IPS x  1/2 OD compression, buy the brass fitting and use a Teflon ferrule and a brass stiffener? 

  • JUGHNEJUGHNE Member Posts: 3,176
    PB/PEX transition fitting search

    Thanks to Kcopp & RobG;  Sioux Chief and Shark Bite have nothing smaller than 1/2" CTS ftgs.  Watts has a series 3515RB-1008 reducing union of 1/2" CTS X 3/8" CTS.  Rated 100PSI @ 180*.  Same as the PB tubing which may see 15 PSI & 120* max. Watts instructions include PB listing and include a tube stiffener for the PEX side.  (Implying it is a little wimpier?) 

    Not having any PEX in stock can someone tell me if  all 1/2" PEX is actually CTS, that is 5/8" OD??

    These are in their Quick Connect cat.  The manifold blocks for the PB is quick connect fittings.  They have held up pretty well for almost 20 years.  I like the fact that no insert would go into the 3/8 reducing flow.  Any comments on these Watts fittings has anyone used these for any application?  Two of the three manifolds are in bsmt boiler room where a drip would be seen and the third manifold is seen on a regular basis

    Thanks again for ideas. 
  • kcoppkcopp Member Posts: 2,748
    yes, pex and poly...

    have the same OD. Its the ID that is different... hence you can't use the same crimp fittings, but you can use the same crimper.
  • Paul PolletsPaul Pollets Member Posts: 3,017
    PB piping

    I've never seen PB with an O2 barrier, where do you find that it does? The Maxxon manifolds were prone to leakage and some failed catastophically, flooding the homes with gooey black boiler water. We've replaced several dozen of these systems (very common in Seattle) by converting the manifolds to either Uponor or SBK manifolds and using 3/8" PBxPex adapter and SS crimp rings to allow the connection with Pex at the manifold. We cleaned the systems carefully with proper boiler chemicals to remove sludge and installed a FPHX to separate the boiler water from the PB system and installed SS pumps on the system side.
  • RobGRobG Member Posts: 1,850
    1/2 od

    I cannot find any 1/2 od crimper or crimp rings. Here are two links that would give you a compression connection (ferrule and brass stiffener). You would then only have to pick a brass fitting to finish

    Good Luck

  • JUGHNEJUGHNE Member Posts: 3,176
    PB O2 barrier

    Thanks for all replies;  The PB tube is  "INFLOOR Heating systems (CTS-00) oxygen barrier tubing 100PSI @180F ASTMD-3309 SE PB2110 SDR-11 .062 9/16/91 D3X" w/foot count markings. Is red 1/2" OD almost 3/8" ID.  The 1/2" size is green with the same markings including "O2-DIN4726 25.08.90./04.38 A." 5/8" OD & almost 1/2" ID.  The supplier didn't think I really needed the PBOX but was all that was on the shelf.  Non barrier tubing was available at the time.  So was I lucky??

    PEX was a "new unproven??" product in the early 90's.  Or they just wanted to clear off the shelf, I don't know but here we are.  Never a problem with the PB, as stated above the CI boiler/blk pipe did not suffer as the change out to mod con showed.

    Manifold issues now, balancing knobs if not stuck will drip.  Plan on new SS manifolds to 1/2" PEX.  Have found "quick connect" for transition..Old manifold used quick connects and worked OK.  Paul you mention 3/8" PB X PX w/crimp rings. Are these also known as "chinch rings" that are applied with the nipper looking pliers?? And do you know the source for such; 1/2 X 3/8 CTS.

    Thanks again.
  • Paul PolletsPaul Pollets Member Posts: 3,017

    I got mine from Chris Rorke at Blueline Supply in Jackson Hole, WY. He stocks the connectors, odicum crimp rings and press pliers for the rings. Glad the O2 barrier worked for you and your system. You lucked out.
  • RobGRobG Member Posts: 1,850
    I am confused

    Is this 1/2" od tube or 5/8 od tube (1/2 cts)?

  • JUGHNEJUGHNE Member Posts: 3,176
    PB sizing


    Sorry for the confusion, these repairs for now are 3/8" ID / 1/2" OD.  It is labeled 3/8" on the red colored tubing.  I mentioned the 1/2" ID/ 5/8" OD (green tube) just for added information concerning the face that PB that was available with O2 barrier.  It is also in the house but will be dealt with later. It is looking like I will probably go with the Watts Quick Connect reducing coupling unless someone has had a bad time with something like this and would like to share.

    Thanks again to all.
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