*PEX Plumbing*
By: AlasKen
15 April 2011

I am adding a bathtub to a 3/4 bath in the basement. In years past I have always used rigid copper and sweat fittings (solder) when plumbing water lines. I was told about PEX pipe from some plumber friends of mine. They said it was all they were using in rural Alaska due to ease of use and the fact that it was much more forgiving to freezing. It is said to expand and not rupture when freezing. I do not have first hand FNV and hope I never do. A close friend in NM has it throughout his house. During this last winter, when NM was hit hard by freezing, his water froze up and, when it thawed, he had no leaks. That sounds good to me.

I got the following information from the PEX web site... http://www.pexinfo.com/

PEX tubing is made from cross-linked HDPE (high density polyethylene) polymer. The HDPE is melted and continuously extruded into tube. The cross-linking of the HDPE is accomplished in one of three different methods.

PEX plumbing has been in use in Europe since about 1970, and was introduced in the U.S. around 1980. The use of PEX has been increasing ever since, replacing copper pipe in many applications, especially radiant heating systems installed in the slab under floors or walkways. Interest in PEX for hot and cold water plumbing has increased recently in the United States.

Advantages of PEX Plumbing:

PEX is a plastic pipe that is very stiff but still flexible and it will make the bend around 90 degree corners in stud walls. I have personal FNV on that. In my case I added PEX to existing copper by sweating a 1/2 inch copper to 1/2 inch PEX fitting to the end of my copper run.

PEX is easy to add fittings to. You have a fitting, a compression ring, a crimping tool, and a crimp gauge go/no go tool. I used the Pro Compression ring which has a red plastic spacer on the end that fits flush with the fitting in order to have the correct spacing. I also used a plastic pipe cutter for cutting the pipe.



To add the fitting...

1. Slip the compression ring over the end of the pipe.

2. Slip the pipe with the compression ring onto the fitting.

3. Crimp the compression ring

4. Check compression ring with the crimp gauge for proper fit. The gauge should slide over the ring but not bottom out. You are checking that it is crimped enough without being over crimped. If it is not correct you adjust your tool until it is.

It really is that easy.

A month ago I added a washer and a sink to my house. I used PEX for this addition. Now, I wanted to connect a tub to this run. I added the faucet to my rough-in using PEX. I used galvanized pipe for the drop and PEX for the supply and the shower. As you can see, the PEX will make a pretty tight bend without needing a fitting. Caution must be taken not to crimp the line. The fitting were 1/2 inch female pipe threads to 1/2 inch PEX compression.


Initially, I just ran the supply lines to the area I planned on connecting. I didn't want the water connected until I was ready to flush the system.

After I had the backer board installed, but before I tiled, I wanted the water hooked up to check for leaks. I also flushed the lines to make sure I didn't have debris before finalizing the faucet install. I am using a Delta faucet which allows for rough in and flush before final install.

First thing I did was turn off the water and drain what I could. These lines were low so they still held water. I just cut them and mopped up the water that didn't get in the bucket.

In order to hook up the water supply lines I need 2 1/2 inch Tee's, 6 compression rings, pipe cutter, and the crimping tool and compression gauge.

I found out the hard way that it is easier if you crimp the supply line from the faucet before crimping the rings from the main line. It was difficult to get the crimp handle into the stud cavity.

After all was crimped in place, I turned the water back on and checked for leaks. No leaks and all was well. I then flushed the system and installed the Delta cartridge into the faucet. I am just using a piece of 1/2 inch galvanized pipe with a 45 degree elbow for the flushing. When I get the tile installed I will have a proper tub spout.

It took me longer to write this article than it did to do the job. I hope I like the PEX system as much in 20 years as I do today. A job that normally would have taken me 3 or 4 hours took less than an hour. Several minutes of that was taking photos for this article.

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