another pex tubing ???

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coolidge

Member
Hearth Supporter
Dec 16, 2008
218
Maine
Ok I got the Onix tubing on order and am going to use some aluminum printing plates to hold it in place and for heat transfer. Now i,m thinking of using the pex with the aluminum built into it. I have to go around my floor joist, they are made of logs. But the pex/alum. will shape to go around. Plus it would be alot cheaper. Thoughts?
 
Pex with aluminum built into it? Are you talking about pex-al-pex? I think most types of pex can be shaped around curves. And pex-a is cheaper than pex-al-pex, especially when you consider the cost of the fittings...
 
Maybe I am getting old and curmudgeonly, but PEX has been around for a long time and is very reasonably priced.
Without saying anything bad about other tubing, I want the tubing that is projected to last for over 100 years, PEX.
 
stee6043 said:
Pex with aluminum built into it? Are you talking about pex-al-pex? I think most types of pex can be shaped around curves. And pex-a is cheaper than pex-al-pex, especially when you consider the cost of the fittings...

Are the fittings used for pex a not compatable with pex al pex?
 
trumpeterb said:
stee6043 said:
Pex with aluminum built into it? Are you talking about pex-al-pex? I think most types of pex can be shaped around curves. And pex-a is cheaper than pex-al-pex, especially when you consider the cost of the fittings...

Are the fittings used for pex a not compatable with pex al pex?

The pex-al-pex compression fittings are not compatible with other kinds of pex. This is also true of the "sharkbite" style fittings. I'm not sure about the crimp fittings, however.
 
I am in the middle of installing pex-al-pex under my floors right now. When I needed to splice the tubing, I used the crimp fitting which I purchased at Home Depot...they were simple solid brass rings and couplings. They did not specify whether they were for pex, pex-al-pex, or anything like that, but I was able to make them fit and crimp them into place. Does anyone think that this is something I should worry about failing once water is added? I knew that the shark bite style fittings did not work on pex and pex-al-pex, but I am certainly hoping that the crimp fittings do......
 
trumpeterb said:
I am in the middle of installing pex-al-pex under my floors right now. When I needed to splice the tubing, I used the crimp fitting which I purchased at Home Depot...they were simple solid brass rings and couplings. They did not specify whether they were for pex, pex-al-pex, or anything like that, but I was able to make them fit and crimp them into place. Does anyone think that this is something I should worry about failing once water is added? I knew that the shark bite style fittings did not work on pex and pex-al-pex, but I am certainly hoping that the crimp fittings do......

You can try a test with compressed air-- get some adapter fittings to allow you to put a standard tire-type Schraeder valve on one end of the run of the tubing, and put a temporary plug in the other. Use an air compressor with a regulator on the output so that you don't hit your pex and fittings with high-psi or a sudden burst. Pressurize the tubing to what you'd want to be comfortable with [perhaps 30 PSI]. Check it with an accurate tire gauge & write down the reading. Then check it again hours later or the next day- if the pressure has dropped any significant extent, you've got some point in the system that is not holding pressure.
 
The fittings for pex al pex PAP have o-rings on them. They are available as a crimp style, or compression, here are a few examples.

You also need that tool which rounds out the tube and cuts a bevel on the end so the o-ring doesn't rip when assembling.

Regular pex fittings without the rings will leak, especially if the tube moves around.

Now Viega Fosta pex is a different animal. It has the aluminum wrap on the outside. A tool removes that layer and a regular brass crimp fitting and copper ring will work on it. Viega prefers you use their brand.

hr
 

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I used the PEX-AL and found it is MUCH harder to bend than the regular stuff the advantage is its self supporting and does not need to be secured as often.
It WILL NOT go up and down around floor joists not even close.
The fittings I used were the compression with O ring and they worked great however they are not available at the box stores just the plumbing supply shops.
 
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