pex fittings, what to use?

[maple1]

it will make short work of expanding the ends for the fittings.

Is that necessary or even supposed to be done with pex?

 

[Highbeam]

it will make short work of expanding the ends for the fittings.

Is that necessary or even supposed to be done with pex?

No. Only the uponor stretch fittings with no crimp ring need pex expanded.

 

[warno]

I have never ran pex before, this is my first install, I was just going off of what a guy from work told me. He said the fittings fit really tight and you have to flare the ends open on the tube a little or heat them to get the fittings in. Is this not the case?

 

[maple1]

I have only used 1/2 & 3/4" pex, in domestic water situations. Slip a ring around the pex, slide the fitting inside the pex, then crimp the ring.

With what I used.

I wouldn't have even thought about flaring with the way the fittings fit inside the pex. I actually thought the 1/2" was on the sloppy side to start with. No leaks though, yet, knock on wood.

 

[DaveBP]

To help clear up some confusion here... Wirsbo (now callled Uponor) uses a unique system to connect their pex tubing. Their fittings are too big to allow the tubing to slip over the barbs. You have to use a special (i.e. expensive) expander tool to stretch the tubing end, with a second sleeve over it, so it will slip over the fitting. You then need to hold it there for a minute while the stretched tubing shrinks back down tight on the fitting. Because of that sleeve the wall thickness over the fitting barbs is doubled. No crimp ring or clamp on the O.D.

Judging from their perennial availability on fleabay, a lot of people buy the tool, do their job, and then flog the tool at auction. The parts and an installation can be seen in airlina's post above.

I have to say that the tubing end can be expanded and then shoved down onto the fitting in close quarters that would never allow a conventional crimp tool to have room to do its job. And no, I've never had one leak. Wirsbo has done it this way for a long time.

 

[warno]

That's probably what my friend from work was using.

Thanks for the info.

 

[Highbeam]

I have never ran pex before, this is my first install, I was just going off of what a guy from work told me. He said the fittings fit really tight and you have to flare the ends open on the tube a little or heat them to get the fittings in. Is this not the case?

You've got the uponor system that some pros use that do enough to justify the expense or you've got the two styles of clamp ring that most people use. Also sharkbites for that odd connection, I now only use them when going from pex to copper.

The brass fittings used with the regular crimp/clamp rings do not fit really tight at all. Barely tight enough to keep them from spinning around on their own. Even after you crimp them you can twist them with effort to allow final fitment.

I've never had one leak either. Wonderful system.

 

[duramaxman05]

I used a few sharkbite and the rest was regular brass barb fittings. I used cinch clamps because i already had the tool that also works on cv boot clamps. Have had zero problems out of them and all mine was 1".

 

[warno]

All good info, thanks everyone.


I have a question now about return temp protection. If I'm pulling too much heat from the water through my heat exchangers I have read I could plumb in a bypass that would allow water from the supply side to run into the return side to maintain a higher return temperature. I planned on plumbing in a bypass after my pump anyway should a problem with the heat exchangers arise. My question is could I just leave my center valve in my bypass section cracked open to allow supply water to go into the return side or is it recommended to buy an actual "bypass" valve to do this?

 

[Scotty2]

Are there different styles of 'expansion' fittings?
I've read that some expand the pipe so that a larger fitting can be installed, thus there is no restriction in the flow at the fitting.
Regards, Scotty

 

[NP ALASKA]

I have used 1" shark bites for 8 years now since installed, about 20 fittings in all

No issues what so ever

Heat all winter in Alaska
Shut system down in summer and they have never offered to leak no matter what temp the water is

Regards