PEX for HW radiator heat supply and return lines?

Bob Bona_4

just use the right kind. A pex/aluminum/pex (PAP) product like Viega's Fostapex or Uponor's MultiCor works best b/c it is very stable when heated. Regular PEX will expand, make noise, chafe, and become like a limp noodle as it gets hotter.

I have become just about flameless these days. My B tank has been replaced with a Mapp gas torch that lasts me over 4 months.

You will need to rent or buy the correct prep and attachment tools to do it.

RonABC_2

PEX for HW radiator heat supply and return lines?

I need to move and replace some supply and return pipes for a hot water cast iron radiator heat system.

Can PEX be used to replace these lines instead of using cast iron or copper? I can find a lot on the Internet that refers to using PEX for under-floor heating systems, but I can't seem to find anything specific about whether it is okay to use PEX for hot water cast iron radiator heating system supply and return lines.

Thanks.

RonABC_2

PEX for HW radiator heat supply and return lines?

Thanks. That helps a lot. I haven't been able to find a definite answer on this anywhere else. I'll check out the pex/aluminum/pex (PAP) products like Viega's Fostapex or Uponor's MultiCor and make sure that's what I use.

MikeyB

PAP

Bob, which PAP do you prefer more Viega,or the Uponor? Likes/Dislikes...Im looking to start using the PAP more in the near future. Just not sure on which one I would use, and Im only looking into buying one of the tools, Thanks for your help

Bob Bona_4

I started

off as a Wirsbo guy back in the day, and still use their Hepex,manifolds, etc. for radiant work. When they introduced MultiCor, I was stoked, and used quite a bit of it, but didn't have the dough for the power crimp tool-the only way to make connections 3/4" and larger-the majority of my work.. I would use it for exposed runs-like for hydroair, feeds to bb's. I used the mechanical fitting ends, and prayed I didn't have to make a sharp bend- there were no elbows I was aware of then, plus w/ the large mech nuts needed it would have made quite a bulky fitting. My supplier bought in the M/C on my request and I was the only customer..everybody else used regular PEX (and was able to be ok with it's drawbacks at high temp). Pretty obscure stuff, nice, but not all I imagined. 1" was not available then to me, and with 3/4 being difficult enough to tool up for, I didn't even want to mess w/ 1".

I actually went back to copper for a while!

Around 2003 ish, I tried the Viega Fostapex, and never looked back ( I used my old 1/2" M/C scraps on a radiant plate job, I still have a coil of 3/4 M/C looking for a home:)). What I like about it is that I can hand crimp up to 1" (waiting for 1 1/4 to be available), and they have so many fitting choices. You can get it in 20' sticks. I don't have to worry about a 2K plus tool breaking/falling off ladders, etc. For less than a third of that price I am tooled to do 1/2" up to 1". The ID on the brass fittings may disturb you but the idea is that you use less of them because of the flexibilty of the tubing, and that makes any extra head loss a wash, or even coming out ahead. When I started to use FP I deliberately made some sloppy crimps of all types to see how goof proof the system was and to see what tolerances I was working with, and was totally impressed. Sometimes you have to think ahead before crimping to make sure you have clearance to perform the crimp action-the tool's handles need room. I pre-fab and bend out temporarily a lot. One drawback I can think of, as w/ any Pex is where to recycle scraps- I save anything over 1 3/4" long (that's as small as you can work with).

Love the stuff. I use it by the mile.

MikeyB

PAP

Great explanation Bob, I thank you for your help, There is a bit of price differance between the tools, Veiga looks like a good candidate for what I am looking for. Thanks again

Kool Rod

Bob- Thanks for sharing your experiences!

- Rod

Bob Bona_4

you''re welcome

One thing I forgot to mention is that the M/C mech fittings didn't allow me to bury them in walls. etc. whereas Viega's crimps can be even used in a pour (not that I'd tempt fate) as told to me by a rep.

Alan(OnVacationInOregon)Forbes

This was

seven years ago when we didn't have as many choices where we used PEX A with Rehau fittings. Each radiator was fed by a dedicated loop off a manifold; one or more manifolds per floor.

See attached photos.

duffy_4

just finished this job,replaced one old boiler and horizontal supplys with 2 new ci boilers and individual pex a pex lines to each radiator