Fostapex with crimps, clamps, and press sleeves?

farnja

I'm getting ready to do some DIY work and know that I would like to use PEX-AL-PEX and most likely Fostapex for my application.

I've tried to wade through all the connection and fitting possibilities, but I'm a little confused on fostapex in particular. I've tried searching, but haven't been able to get an answer.

I'd like to know which of these combo's are possible, assuming I'm using 1" Fostapex:

1. Hand Press Tool with Press Coupling with no fostapex prep tool.
2. Hand Press Tool with Press Coupling with Fostapex Prep Tool to trim back first inch of aluminum exterior on Fostapex.
3. Ratcheting clamp tool with 1" Stainless Steel clamps (not sleeves) with 1" Crimp/Clamp Coupling using the Fostapex Prep Tool to trim back first inch of aluminum exterior on Fostapex.

If case #3 is possible (and recommended), it'll save me a few hundred dollars in tools and fittings. I know 1 or 2 are probably quicker, but this (hopefully) a one-time thing.

Thank you!

Ironman

I'd recommend that you contact Viega or Rep to make sure you get the correct answer. Their pex-al-pex and fittings are different from others.

hot_rod

FostaPex is not really a Pex al Pex. It is a standard pex tube, with aluminum wrap and a PE coating.

PAP usually has the aluminum layer built into the tube itself, not wrapped around, so it is the same OD as regular pex. FostaPex is a larger OD due to the additional wrap.
Once you strip away the aluminum and PE you have a standard pex tube.
Manufacturers typically want you to use their tube with their fitting and crimp collar.

\That being said I have used standard copper pex crimp rings on Fostapex once the jacket is stripped it works.

The Viega fittings seem to have a finer rings on the fitting compared to others also.

It's your call I suspect Viega will insist on their fitting and ring to maintain any warranty.

Although they do not really have a good solution for putting FostaPex into compression fittings on TRVs etc. Unless you adapt to copper first. I modified my stripping tool to strip away enough jacket to make it work with compression fittings.

My supplier will also bring in straight 20 foot lengths of FostaPex in red or blue, straight lengths are easier to make look like copper

farnja

Thanks Hot Rod!

j a_2

Hot Rod great post..I have used it but never was really fond of it...just something about the crimp connections I don't like....To the OP what are you running in one inch..? Get a copy of B&G little red book it is an extremely useful booklet or get pumping away written by Retired Dan

j a_2

https://images-na.ssl-images-amazon.com/images/I/51pEGzAplFL._SX322_BO1,204,203,200_.jpg

farnja

Thanks j a -

Pumping away (and Dan's "Hydronic Radiant Heating") are what set me off on this topic. Did not expect them to be as interesting as they were!

I'm running 1" for a primary loop around my boiler. Will be about 50 ft with a few T's, etc.

hot_rod

farnja said:

Thanks j a -

Pumping away (and Dan's "Hydronic Radiant Heating") are what set me off on this topic. Did not expect them to be as interesting as they were!

I'm running 1" for a primary loop around my boiler. Will be about 50 ft with a few T's, etc.

Just remember the ID of pex, and Fostapex is much smaller that copper tube. What kind of flow rate do you need in the primary loop?

farnja

I'm hoping to get about 7-8 GPM.

Based on my heat-loss estimates, that should be enough, especially if I'll accept a 25, 30 degree drop. But heat-loss is inexact...

Yes, my alternative is 1" copper, which would probably get me to 10 GPM.