PEX-A & PEX-B

[Nukedaddy]

I know the difference in the formulation method for the two kind of PEX tubing. And that PEX-A is the one that uses the Wirsbo-UPONOR type of fittings with expansion rings instead of the compression rings, clamps or Sharkbite fittings used with PEX-B (Silane process) tubing.
My question is somewhat theoretical or speculative. If PEX-B is used with the expansion fittings instead of the intended compression types, will it necessarily be a leaker? The tube end is reinforced with the expansion ring. Both A and B tubing have material memory. PEX-A may have “more” memory than B, but is the difference really all that much?
I want to hear from the combined experience of our august members. I can go with the “because the manufacturer says to” or “why would you want to take a chance”. Both reasons are valid.
BUT: I want to know if anyone has specific knowledge of tubing failures due to using expansion fittings on PEX-B.

 

[arctic bill]

What is difference between PEX A and PEX B?


Again, the main distinction lies in the manufacturing method, which is what assigns an A, B or C to PEX. PEX A is made using the Peroxide, or Engel, method. PEX B is formed using Silane, or Moisture Cure, method. This is the most common PEX pipe type out there.

I have used Wirsbo-UPONOR what you call pex a, and found it to be very good, I highly recommend it. what real does it for me is that labor and material are guaranteed for 25 years by the manufacture. the other B i have no experience with.

 

[SHEPLMBR]

Pex b is not expandable. It doesn't have the "memory" to shrink back down. However you can crimp pex A

 

[Nukedaddy]

So has no-one any direct experience with the use of PEX-B with expansion type fittings?
As Sheplmr remarked, PEX-B is not commonly used for expansion fittings and I have read some reports that indicate the PEX-B resin is inferior to PEX-A. One data item was that if kinked or crushed PEX-B is ruined, possibly due to a lack of material memory and must be cut out. But PEX-A is repairable by using a heat gun to relax the resin and restore the original shape.
It is unclear so far if PEX-C as sold by Nibco is better or worse than either A or B but Nibco does not make or sell an expansion type of fitting. The reason I asked, starting this thread, was that a friend bought a 100’ roll of white PEX-? And ran it as a water service underground. He borrowed an expansion tool and expansion ring and adapter from a neighbor. BUT: He did not verify the PEX-? as PEX-A. So here’s the deal. He expanded possibly PEX-B tubing WITH A PEX-A expansion ring over it onto an expansion type adapter. It is not leaking at 110 psi. Is the joint “gonna leak, for sure!”, “might could maybe leak” or “it ain’t leaking now, don’t get your panties in a bunch”.
BTW, he live a couple hundred miles from me and I cannot go dig some up for him and read the tube marking to know for sure.

 

[Twowaxhack]

It’s best to follow the installation directions of the manufacturer.

If he expanded pex B it’s an inferior connection to A. It will most likely fail.

Maybe your friend could borrow a shovel from the neighbor he borrowed the pex expander from and dig it up.

 

[Nukedaddy]

And PEX- B is the inferior resin product when compared to PEX-A. I am waiting to hear back from Nibco about PEX-C. So far no response as to its suitability for expansion fittings. But Nibco doesn’t sell expansion fittings and so far is the only maker found for PEX-C.
All I am trying to do is get enough info to make an informed recommendation to my friend as to whether he digs up a new water service that is not currently leaking or not. Will the expansion ring/collar be sufficient to grip and seal the underground connection long term even if the tubing is “B”. It is not leaking now at 110 psi.
So far no-one has any direct experience with the misapplication of the inferior “B” resin tubing on expansion fittings, only testaments that it is not recommended. That is good, I read that too, but it doesn’t help making an informed decision to recommend digging it up for replacement.

 

[Twowaxhack]

And PEX- B is the inferior resin product when compared to PEX-A. I am waiting to hear back from Nibco about PEX-C. So far no response as to its suitability for expansion fittings. But Nibco doesn’t sell expansion fittings and so far is the only maker found for PEX-C.
All I am trying to do is get enough info to make an informed recommendation to my friend as to whether he digs up a new water service that is not currently leaking or not. Will the expansion ring/collar be sufficient to grip and seal the underground connection long term even if the tubing is “B”. It is not leaking now at 110 psi.
So far no-one has any direct experience with the misapplication of the inferior “B” resin tubing on expansion fittings, only testaments that it is not recommended. That is good, I read that too, but it doesn’t help making an informed decision to recommend digging it up for replacement.

If your friend expanded pex B then he probably screwed up, again you refer to the manufacturer for specifics on their product.

Zurn says you can expand their pex B......but zurn sucks IMO and I’d never use zurn pex. I’ve found a lot of zurn and Nibco pex leaking.

 

[Nukedaddy]

Well you certainly have lots of opinions to share. You say you have had trouble with Nibco? Isn’t that the one source of PEX-C? I have not seen a response from Nibco yet as to whether ”C” is an expandable product. Has anyone else had bad experience with either Zurn or Nibco PEX system? I know Zurn is more prevalent in the West. I wonder what market share each manufacturer has?
Does anyone know who the #1 PEX tubing and fittings system manufacturer is? It may be that #1 is simply the brand carried by the big box home centers based only on price.
I heard from my friend. On the basis of my advice and that of a couple of manufacturers he dug up the one underground expansion fitting and applied an Oetiker type one ear clamp to the OD of the expansion ring to prevent any material relaxation. And then, by chance, he found a short cut off piece of the tubing that had been tossed in the ditch during backfill. Yep, it was PEX-A all the time.
Thanks to all for the collegial review.

 

[Twowaxhack]

Nibco is the worst pex I’ve ever had to deal with.

I’ve done a lot of work in a lot of places for a long time, all my life.

So naturally I’m going to have an opinion. Most of the time I’m right.