If your reason for replacing the copper is due to aggressive water PEX may not be the best choice because all the end terminations on a PEX system are made of the same grade of copper as the copper pipe, thus a PEX system is vulnerable to the same types of problems from aggressive water as is a copper system.

A better choice would be to use CPVC which has no copper components in the system.

One the other hand, in my humble opinion, if you have aggressive water that is eating up your pipes, what is the long term health problems associated with that water. I would much sooner look for a water treatment system that would eliminate the water problems rather than seek a pipe material that might be more tolerant.

Lazypup:

Thank you for reply and concern. First off my water is fine for consumption, it's just that the particular water chemistry is slightly aggressive to copper. It's really a combination of many factors (ph, temperature,dissolved solids,calcium ion concentration, and thin copper pipe).

Regarding the fittings being made of copper. That will not be a problem for many reasons, but primarily because all my pipe failures have occured where the pipe is horizontal. I have never had a failure on vertical pipe, nor at any terminations.

CPCV would challenge my plumbing ability more that PEX.

Having heard my response, can you help me with my specific questiona regarding the pex tools, and my plans to re plumb?

Thanks,
Don

The PEX crimping Tools work look very similar to a 24" bolt cutter and they work in a similar manner. The fitting and lockring is put on the tubing, then the jaws of the tool are placed over the lockring and the handles compressed in the same manner as cutting a bolt with bolt cutters. They can be very challenging to work in a tight spot however in most cases the tubing can be pulled out to an accessible place, the fitting made up, then the tubing is reinserted into the desired location.

You must also have a PEX "Go No-go" gage and each joint must be checked with the gage to insure it was crimped correctly.

You can download the complete PPFA (Plumbing Pipe Fitting Association) PEX installation handbook in PDF format from the following website:

http://toolbase.org/PDF/DesignGuides/PEX_Installation_Handbook_2006.pdf

I have replaced a couple pieces of pipe with PEX and have thought about replacing therest of it. The copper stubouts have me baffled. Why is it nobody makes a brass stubout?

I have thought about making my own. an elbow 1/2 PEX x 1/2 MNPT and a 1 or 2" brass nipple. a sheetmetal bracket would be brazed or clamped to this to allow inserting the pex end into the wall and then screwing the bracket thru the sheetrock into the stud. This could get expensive, I have 4 sinks (2 each) and 3 toilets (1 each) 11 total.

The outside faucets would be another issue. how do you mount one onto a brick wall?

Hello Again:

Do I need an unroller, or is there a technique that I can use to properly "unroll" the tubing??

Thanks,

Don

No, you don't need an unroller.

On the other hand, don't expect that you can just throw a roll of PEX on the ground and pull one end completely through your house - it can get tangled.

Depending on the length of the room I was working in and the length of the run, I would unwind about 10 to 15 feet at a time and pull that through, then unwind a little more, etc.

If you have another person helping you, then they can just feed it as you pull.

You must exercise care when pulling the pipe, especially when pulling around a 90deg bend because you the pipe can kink. When making a 90 deg turn it is best to pull the tubing to the corner, then pull the next section rather than trying to pull the tubing around a hard bend.

Lazypup:

Are you saying in regards to a 90 degree turn that I should cut the tube and use a 90 degree fitting?

thanks
Don

no..no do not cut the tubing but you must be careful when pulling the tubing around a corner to insure it does not kink.

There is also a minimum radius allowance for bends in the tubing. There is a chart in that installation handbook that defines the bend radius

Lazypup:

OK I think I get it. e.g If I'm running the tube in my basement along or through joists I can carefully run it directly from the coiled tubing, but when I go through the floor making a 90 degree turn I should first gather some extra tubing at the last joist before I carefully pass it upstairs?

Don

Manifold Question:

Can I gang together two manifolds of the same size copper pipe (using a large diameter say 1-2 inches would be better?)that would have different sized pex terminals i.e. mostly 1/2" but at least one with 3/4"?

This is the type of manifold that I would sweat two together but they would have different sized terminals:

http://www.pexsupply.com/categories.asp?cID=519&brandid=

Would this cause any problems?

Thanks
Don

When running a manifold system all the lines are sized much different than when running a main and branch layout..

That it why most jurisdictions require the installer to be trained in the proper installation of PEX.. At a minimum,,download the installation manual and follow it in detail otherwise your going to end up with a big mess.

I have downloaded the manual, and I don't see where my questions are addressed. If I missed something, please tell me what page it's on.

Thanks,
Don

In the "INSTALLATION HANDBOOK: CROSS LINKED POLYETHYLENE (PEX) -HOT AND COLD-WATER DISTRIBUTION SYSTEMS.

Tubing bending radius......................pg 6
Manifold sizing table..................... PG 9
Fixture Line sizing........................PG 10

Lazypup:

I thought the table on page #9 was referring to the diameter of the manifold needed for a certain level of maximum demand (velocity) of the water.

I wanted to know two things. Is a larger diameter manifold than required ever a bad thing? Secondly, can I mix the output terminals with both 3/4 inch and 1/2 inch nipples?

Thanks
Don

If you are running a PEX manifold system I fail to see where you will be using 3/4"?

Standard fixture runs are 3/8" & 1/2"

The size and number of the output nipples is determined by the MFG specifications for the manifold and the main line in the manifold is designed by the manufacturer to supply full volume and pressure for the max number and size of taps on the manifold.

There would be no advantage in oversizing however, if you connect two manifolds in series on a common feed that effective reduces the feed to each manifold by 1/2 and should not be done.

Hi:

Here's why I need two(one hot & one cold) 3/4" terminals:

My current game plan is to modify my current copper plumbing with PEX. I have a two story home with an exposed basement ceiling. I can clearly see where the ½" copper pipes branch off the ¾" main to the separate sites of the kitchen and ½ bath above on the first floor. I am considering disconnecting and sealing off the current ½" pipes that feed to the kitchen and re plumb PEX from a manifold to each fixture using the same holes through the floor above. The ¾" copper would then be connected as a separate line in the manifold as well to continue to supply water to the second floor.

The reason IÂm not thinking of redoing the 2nd floor plumbing immediately is because it presents some major obstacles for my limited plumbing and carpentry skills. The current pipes are hidden in the walls and ceilings, and I donÂt know exactly where they are.( Ideally if I knew where they were I could cut them out and replace them with PEX tubing, fishing them through the same holes in the walls and joists.) Instead IÂm considering a new route maybe through closets etc. to reach the upstairs fixtures.

Don

I fully understand what you are attempting to create. It is called a hybrid system where you will continue to use the main and branch layout for part of the structure and a PEX homerun system for another part. The point I am trying to make to you is that there is no reason to connect the 3/4" branch lines to the manifold. If you want a shutoff valve on those lines simply install a ball valve as a zone shutoff and use the manifold to feed the new individual fixture lines.

I need one water source to supply two different lines (copper & Pex), and I was thinking of using the manifold to accomplish this split. Is there a better way?

Don

A manifold is nothing more than a group of two or more branch connectors with or without valves built on a common body. The exact same thing can be done by installing a Tee on the existing main line.

If you insist on getting a manifold large enough to support 3/4" lines you will need to move up to a commercial manifold rather than a residential one, which would dramatically increase the cost. For a fraction of the difference you could install tee's.

I am currently using pex to plumb my new construction home , I am using 1
main manifold and 2 remaote manifolds . The main supply lines that run from
one manifold to the next is 3/4 " . I am using 1/2 " for the fixtures and 3/8"
for the toilets and icemaker . I ordered my materials from Mountainview
Supply and they were extremely helpful with all my ordering and questions .
I also found their prices to be very competitive .