Confused about PEX

BOUTYM

With my bathroom remodel project I'm using PEX with the black crimp rings. No big deal there, but I was thrown for a loop yesterday at the plumbing supply house when I went to pick up some oxygen barrier PEX to replace some bad copper lines for the baseboard heat. I was under the impression that for the most part PEX is PEX when it came to connections, but this guy is telling me that there's expandable PEX, non-expandable PEX, variations in PEX tubing by manufactuer, etc. Said if I use manufacturer X's tubing I can't use manufacturer Z's fittings, etc., etc., etc. He tells me I can't use the black crimp rings with expandable PEX.

So now I'm sitting here with this "well crap" attitude and thinking of just doing copper since I know how that works.

BOUTYM

To add to my confusion post, I can find no information anywhere that talks about all these differences in PEX the counter guy was whipping on me.

rjniles

You are being deked.

There are 3 kinds of PEX for potable water:

PEX-A, PEX-B and PEX-C

They are different manufacturing process types and all can be used with Wisbro (expandable) or crimp ring systems.

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Coastal South Carolina

TheEplumber

He's telling that there are different methods of joining pex: expansion vs. crimping. These are done by different manufacturers And a different pex is used on heating systems

BOUTYM

Is there such a thing as oxygen barrier PEX that can be connected with methods other than expansion, such as crimp rings and such? I don't particularly want to invest in the expander tool unless I have to for such a small amount of repair work.

BOUTYM

Actually, if the compatibility charts I'm looking at are accurate, it appears as though just about any type of PEX is compatible with crimp rings, but it's the fittings that make the difference.

gbwillner

It's not so complicated. There are 2 basic ways of joining PEX- the expansion method and the compression method.

The expansion method is better and used more by professionals- but requires VERY expensive materials. For a single project there is no reason on earth why you should use this method. All PEX tubing (barrier and non-barrier) have the same outside diameter (OD), so all will work (theoretically) with either the compression rings, clamp rings, or "sharkbite" systems. I think initially there were problems with slight variations in size and you had to buy the hardware from the same maker of the tubing. This is certainly no longer true. Personally, I use the compression ring system. It's permanent, easy to use/install, and cheap.

The other point others have alluded to- you are wasting money with O2 barrier PEX. That is necessary for hydronic heating only.

One caveat to what I posted above- PEX-AL-PEX actually has a slightly different OD, so needs special hardware.

Good luck.

BOUTYM

Thanks much for the info. I knew PEX-AL-PEX was a slightly different animal, but I couldn't figure out how there could be so many variants of what's been around for some time now. I would have figured that there would be some standardization by now.

I do have some short runs for hydronic heating that I need to do though.

gbwillner

You mean on a different system though, right? O2 barrier pex is only for re-circulating systems (goes from the boiler to radiator and back, etc.).

BOUTYM

It is a re-circulating system.

BOUTYM

Ended up using 3/4 O2 barrier with crimp connections and it's working out fine. That 3/4 stuff is a bear to work with in tight quarters though, but I was working with it by myself which made it harder than it needed to be. Having someone to handle the coil management task would be good.