Pex-al-pex

STEAM DOCTOR

Good morning. My experience with pex has been with the "traditional" pex. I dont have any experience with al pex(I don't think my supplier even carries it and the counter guys call it home depot pex). My limited research tells me that the pex al pex has greater flow rates than traditional pex and it's obviously easier to work with. It would be greatly appreciated if anyone would be kind enough to share their knowledge and experience.
Thank you.

Bob Bona_4

PAP made me like piping again 12 years ago. My B tank takes up space in the garage and I only carry a Mapp with me. If I work with 1 1/4 and up that's minimal and only then I crack out the old B tank. I buy sticks of Viega Fostapex by the bundle. Love it. Flow rates are same as "regular" pex. The premise is you use less fittings because of bendability. I have had 0 problems with joints in the 12 years, and have been using EP plastic fittings for 4 years now with no issues. I only use regular pex for radiant low temp like floors. Before the Viega FP came out I used Uponor MultiCor PAP but they didn't have crimp at the time I believe, and where I could use a mechanical joint had limitations, and no elbows were available. Once I got the Viega reamer and the hand crimper, it was FP.

STEAM DOCTOR

Thanks. How bendable is pap? For example if I am installing baseboard and the holes are under themiddle of the baseboard, can I make a U turn with the pap and a 90% turn into the hole? Thanks

STEAM DOCTOR

Also, what needs to be done to prep ?

Bob Bona_4

You can do about a 6" radius with 3/4, little less with 1/2". Like everything, you develop a technique to make things come out decent. I wouldn't dream of bending it above the floor in a bb situation tho. Best to use sweat x pex 90s.

With FP the outer casing gets removed by the reamer so the fitting can slip on. With MC, you have to ream/bevel the ID so as not to rip the fitting o rings on insertion.

STEAM DOCTOR

Thank you. Didn't think it would be that bendable. Never hurts to ask

Ironman

I have literally run countless miles of it with no problems whatsoever. I generally use the Roth brand which R.E.Michel carries. This is a larger diameter than regular pex (except the 1/2") and requires the matching fittings. It does not require stripping the outer layer like FP does. Instead, you simply ream the pipe with their beveling tool to prevent tearing the O rings in the fittings, then press it.

Bending in the 1/2 - 3/4 sizes can can done with a soft copper ratchet bender for a neat tight bend. The diameter on the 1" is slightly too large to fit a bender so you have to use your knee or a fitting.

You can get a manual lever pressing tool that does several sizes relatively cheap or you can get pressing tongs if you have a REMS pressing tool. I don't know if any other press tool has the tongs available.

Pex-Al-Pex has about the same rigidity as soft copper and therefore requires less strapping or stapling.

Another benifit is that it has about the same lineal expansion as copper: generally, about 1" per 100 feet with a 100* temp rise. Regular pex has 12 times that much, which can really be an issue on long runs.

PAP is the only tubing that I use on in-slab floors. It stays where you bend it which is a real advantage over regular pex. For staple up, the regular stuff is easier to use.

Oh, one more thing: you can use the standard R-20 1/2" manifold connectors with the 1/2" stuff since it's the same diameter as regular pex. It just requires a little more tightening. So, you don't need a special brand of manifold, though Roth has them.

Hope this helps.

Bob Bona_4

Yes, 1" gets the knee or foot mandrel here too. Plan out your joints so you can pre fab stuff if you can't get the tool in to crimp.

STEAM DOCTOR

Thanks guys. I am currently looking into the fostapex. I already have the ridgid Propress. Just need the pex heads, prep tool and some fittings. All of the above are readily available at supplyhouse(pex supply). Only thing I am having trouble finding is the actual tubing(pexsupply has but will take week to ship).