Pex - Al - Pex help please

[Huskurdu]

My brother-in-law is attempting to install radiant floor heat in his new home.....he asked me (like I'd know) how he is supposed to bend the 1/2" pex-al-pex without it kinking in between his floor joists. He said that this stuff is really hard to bend and if you make too small of a 180 turn with it, it kinks. He's got this stuff wedged between the 16" on center floor joists for now, but really needs to get them on 8" centers...any ideas?

 

[deerefanatic]

A tubing bender should do the job.... After all, you're working with plastic-covered aluminum tube there.........

 

[free75degrees]

I have never done any radiant floor heating, so this is just a total guess - could he skip every other row so that he has a larger turn radius and then when he gets to the end go back and do the rows that he skipped?

 

[Huskurdu]

A tubing bender should do the job.... After all, you're working with plastic-covered aluminum tube there.........

You're serious?? Wow, didn't see that coming. I've never worked with the pex-al-pex before. I thought it was more like pex than metal tubing....hmmm....thanks for the info, I'll let him know.

 

[Huskurdu]

I have never done any radiant floor heating, so this is just a total guess - could he skip every other row so that he has a larger turn radius and then when he gets to the end go back and do the rows that he skipped?

He might have to do that...I'm going to stop up his place tonight and take a look at this stuff. I've never seen this before so it should be interesting. Considering how hard it will be to work with, it seems odd that he given this for wood floor heating...seems that a regular O2 barrier pex would have been much easier to install.

 

[Aiken]

This site has a lot of information on installing radiant heat

http://www.radiantdesigninstitute.com/

 

[DaveBP]

Norm, There are some good diagrams in this manual for threading pex tubes through joist bays. Lots more info, too.

(broken link removed to http://www.theradiantstoreinc.com/image/Manual_of_Modern_Hydronics_Section_1_4.PDF)

 

[Huskurdu]

Thank Aiken and DaveBP for the links....I'm checking them out now. The Manual of Modern Hydronics has got some really good detail in it. The other site I haven't checked out yet.

 

[deerefanatic]

A tubing bender should do the job.... After all, you're working with plastic-covered aluminum tube there.........

You're serious?? Wow, didn't see that coming. I've never worked with the pex-al-pex before. I thought it was more like pex than metal tubing....hmmm....thanks for the info, I'll let him know.

Well, I won't say that it's stiff like metal, but it has metal in it and has memory when bent.... so a tubing bender would work well....

 

[Huskurdu]

A tubing bender should do the job.... After all, you're working with plastic-covered aluminum tube there.........

You're serious?? Wow, didn't see that coming. I've never worked with the pex-al-pex before. I thought it was more like pex than metal tubing....hmmm....thanks for the info, I'll let him know.

Well, I won't say that it's stiff like metal, but it has metal in it and has memory when bent.... so a tubing bender would work well....

I stopped up to his place last night. That stuff is quite different than I expected. We figured out how to route it so that he doesn't make any hard bends so he can live without the tubing bender, at least for now.
Is it 'normal' to use pex-al-pex for under (wood) floor radiant heat? It seems like a bit of overkill when the cheaper stuff would work just as well.

 

[Willman]

Is it ‘normal’ to use pex-al-pex for under (wood) floor radiant heat?

Its normal for a suspended tube install. Its what I used with ultra fin. It will not sag when up to temp. It is a bear to work with. I ran mine perpendicular to floor joists 30" c to c. Pulling it through was a chore, didn't need to work out after that day.
Will

 

[Jim in CT]

The bend within a joist should be easy enough to do by hand. you can curve quite a bit before kinking it, if you're careful. When you're feeding it through holes in your joists a liittle liquid dish soap lubes the wood nicely.
Jim