Pipe options - Pex, Pex-Al-Pex, Copper.

As mentioned in other threads, I'm planning a steam-to-hot water conversion.

Today's question is about piping choices. My current plan is to keep the existing steam radiators/baseboards on the 1st floor and run hot water into them, keep the existing hot water baseboards in the finished attic, and add baseboards for the finished basement. Maybe add a section of Ultrafin in the bathroom.

I'm trying to figure out how to plumb all this. My initial plan was to just use copper, as it's what I'm familiar with, and have done my share of soldering copper pipe. However, it seems that in retrofitting my old house, Pex would be much less time consuming. However, I've never worked with Pex before and have many questions.

First off, what's the general opinion here of Pex vs. copper?

Second, I know that one concern is oxygen penetration. My understanding is that appropriate Pex has an oxygen barrier layer, is that adequate in your experience? Have you had problems with this? Is Pex-al-Pex any better?

Third, is there any reason to use Pex-al-Pex? From what I've ready it seems a bit better on the oxygen issue, but is much more stiff (more like copper pipe) and harder to work with, giving up a lot of advantages that Pex has over copper.

Fourth, there seem to be a number of different systems of fittings. I've had someone recommend Viega (sp?), there are others. Which have you had good/bad experience with?

Fifth, Which specific tools are necessary for work with Pex:? I know I'd need the crimper/compressor tool itself, as well as a cutter, are there others?

Sixth, are there good books and/or videos out there that teach how to work with Pex? Not system design, but actual installation.

Finally, are there fitting available to go from copper, to Pex, to iron pipe (for the old steam radiator hookups)? When going from pex to copper or Pex to iron, do you need a dielectric coupling? Or does the pex act as it's own dielectric?

Thanks.

 

Don't use regular Pex (without an oxygen barrier) if you will have any ferous materials wetted in your system.

Some people advocate using a dielectric union between steel and copper, but most people omit the union and live happily everafter. I would omit it.

Some of your other items might be efficiently researched on Google. (Google is your friend.)

 

Another question - any particular brand of Pex that people like?

I've tried googling, but mostly get ads for the various products. Was hoping for more unbiased feedback.

 

PEX-AL-PEX is the gold standard. While it is less flexible than PEX without the aluminum barrier it is still far more flexible than rigid copper. It can be run through holes drilled in floor joists with little trouble. The Uponor system of expanding the tubing to attach to fittings is a proven method and in my opinion superior to many of the "crimp ring" systems. Unfortunately it is also more expensive for the expanding tool but I have heard that it is possible to rent the tool or buy it used and then resell it.

 

Not sure yet about Pex or Pex-al-Pex, but the Wirsbo-Uponor expander seems like the way to go. I'll be stalking eBay for a deal on the tool. It seems like the 2 tools I need are the expande itself and a cutter. I have a ratcheting cutter that I got from Lowes for use on PVC, will that work, or do I need something different? Are there other tools I need?

Thanks,
Juliean.

 

What are you unsure about? Regular Pex can't be used with systems that contain ferous parts - so you should forget that option.

 

By Pex I mean Pex with an oxygen barrier. haPex is the Wirsbo-Uponor brand. The non-barrier Pex is right out. The alternative is Pex-al-Pex. I'm wondering how flexible the latter is.

The main reason I want to use Pex and not just go with copper is for ease of installation the time savings of not having to carefully measure and fit every part to within a fraction of an inch. How much leeway does one get with Pex-Al-Pex?

 

As I mentioned in another thread,
Pex can creak and tick when the water in it changes temperatures. PEX has a great deal of thermal expansion.
Pex-al-pex (composite, Uponor MLC ) control that expansion with the the aluminum layer.

The PEX expander is NOT compatible with UPONORS or any other composite pipe, don't even try it. The crimp rings used on this stuff are steel and about an 1 1/4" long.

 

Could you clarify this? The only expander I know of is the Wirsbo-Uponor "ProPex" expander, which they advertise as usable both on Pex (haPex) and Pex-Al-Pex (the aforementioned Uponor MLC). Is there some other tool out there that's also sold as an expander?

 

To the best of my knowledge, MLC requires the multipress tool.
The alum. liner will be damaged by expanding it.

The entire line of fittings is different

 

You are right, I misread a different website.

Too bad, I was hoping one tool would allow me to work with both.

There seems to be very, very little info on the Uponor website about MLC - there's the instructions for their MiniPress tool, a spec sheet that says "refer to installation handbook" and that's about it. All their design and installation manuals only address haPex. For example, there are clear instructions for minimum bend radii for haPex, but I can't find similar for MLC.

PS The price on the tool is also staggeringly different. A manual Pex expander is about $290 new, and I can find it for under $200 used. An electric expander is about $675 new, and I've seen it for about $490 used. The MLC MiniPress is well over $2000, new or used. Decisions, decisions...

 

Watts Radiant has the PEX-AL-PEX and they have compression style fittings for the pipe.
They also have more details on the instalation of the pipe.
They are not cheap, and you want to plan it out right but that is an option.
There are others as well, it seems to all be made in china anyways...

Do a google on PEX-al or Composite pipe.

Before Ipex pulled the plug we used Kitec a bunch, but they had some issues in the potable water market which I think lead to the demise of the line. Shame I have all the tools and a large inventory of fittings for the pipe still.

 

Copper is fun!

Unless you do it for a living and need to make a profit on your time (copper slower than pex), or do not want to pay for the copper cost...

I did mine in copper... I like the rigidity and it doesn't creak like pex can...

Rmpl

 

Problem is it needs to be type L (at least up here anyways), many customers don't have the stones for a few hundred feet of 1 1/2" type L copper and fittings.

PEX (PEX-AL) generally has nice wide radius turns, much better for flow.

Copper is nice, but not for me :-)

 

Wouldn't / couldn't Watts Onix be an option here?

Watts Radiant - Onix

Pretty much the same as working with heater hose under the hood of your car...

Yes, a bit more expensive, but when you consider that no special tools are needed, it begins to look more attractive.

Or was there a reason I'm missing that it wasn't suggested ?

 

Never heard of it. Will have to research it some, but is it suitable for just running from point to point? Or is it meant to be buried in concrete for radiant floor applications?

 

Probably not suggested for reason(s) other than the one I can think of, which is that it has a lot of detractors. Probably moreso than any other tubing.

 

Please elaborate... I've not used it personally... and haven't heard the 'detractions', other than the price is higher.

 

Me neither. IIRC it was something about premature breakdown. Think rubbery sludge. Maybe that problem has been addressed. Don't know for sure.

 

Many years ago, before watts made the stuff themselves, goodyear made it.
Problem is goodyear changed the recipe a bit, and the stuff broke down. Caused some floods, bad feelings etc.
This was all dealt with by insurance and lawyers etc...

It was Orange, and called entran from what I remember.
The black stuff has not had any problems that I know of... other than the holes from staple guns (kinda self inflicted wounds).

If I had my way I would use this stuff all the time, it does come in 1" but is very expensive and the fittings get silly.

Great if your hooking up high temp baseboards or kickspace heaters, as it has essentially zero thermal expansion at these temps. It is listed to only 180, but will take upwards of 600 degrees I am told (not going to try that thanks).

If you can use it selectively it can be your best friend.