PEX Tubing: An Installer's How To

A Little PEX Background

PEX Piping, officially known as "Cross-Linked Polyethylene," was first developed in the 1960's.. Although an old technology it is only recently being used in U.S. plumbing. One thing that it is good for is the installation of radiant heat systems.

PEX is a bendable plastic pipe that has been toughened by a special chemical process that gives strength to the polyethylene. This product has been swiftly gaining popularity to serve as a supply pipe for plumbing use in residential areas. The piping is able to withstand a wide temperature range all the way from subfreezing to 180 degrees F. The installation of PEX pipe is relatively inexpensive so you can kiss that high plumber’s bill good-bye! Another benefit is that PEX piping is quieter than the fixed pipe systems traditionally used. PEX connections are much simpler than soldering or gluing fixed pipe and can bend around corners reducing the need for joints which is where most piping eventually fails. It is used world-wide for heated drive ways or sidewalks to melt snow in adition to many other radiant heat applications.

PEX can be used ideally in hot as well as in cold water systems. It has become popular with skating rinks and commercial refrigeration due to the reduce risk of breakage from freezing. It is best to check with your local authority if you want to install PEX, as some building codes have not been changed to use this product. PEX is not suitable for outdoor, above ground use because it has to be kept out of direct exposure to sunlight.

Another big benefit of PEX is there are fewer fittings to work with making it simpler and easier to use. A great deal of plumbing problems will occur at the joints. Thankfully, PEX's flexibility enables it to have fewer joints.

On To Installing PEX Tubing

PEX uses a crimp-ring/compression system. It will help to make tightly sealed connections that are permanent and leak proof. First a strong brass fitting is placed into the end of the tubing. Now make use of a crimp tool that has a positive interlocking jaw action, then crimp a copper ring onto the pipe.

Tools Required

You should have the following tools on hand:

• Full-circle crimping tool
• Utility knife
• Copper manifolds
• PEX crimp fittings
• Shutoff valves
• Flexible tubing cutter
• Go/Go-go gauge
• PEX supply pipe
• Transition fittings
• Copper and plastic hangers

Making Pipe Connections

• First thing to do is to measure and cut tubing. Take care that you create NO burrs (if you have a good cutting tool, this will help prevent these). This is a case where cheap or improper tools can cause a bad connection.
• Place the crimp-ring onto the piping. Hose clamps are not appropriate.
• Insert fitting into the tubing all the way to the fitting shoulder.
• Slide the crimp-ring roughly 1/8" to 1/4" from the end of the pipe. Outside of that range can cause a weak connection resulting in leakage.
• The last step is to use the crimping tool to compress the ring onto the tubing. It is important to maintain a 90 degree angle and ensure a completely closed crimp-ring.

The beauty of PEX plumbing is that it can be installed, reapaired and maintained by the homeowner much more easily than fixed-pipe can be. It can't be stressed enough to use quality tools that are in good shape, otherwise you risk a future of leaking pipes.

Don't Forget To Inspect

When you are done you must inspect all joint work. It is quite important that you finish the joint job correctly. Here are some things you should look for:

• A proper crimp at each tube's ends.
• ensure enough ribs are covered.
• Crimp tool is not at a 90-degree angle.. The piping wil have been dented and the ribs not completely covered
• Signs that the crimp-ring was not properly covered by the crimping tool. The ring will be distorted and not create a uniform crimp.
• All tubing has been squrely cut. Fitting ribs will be exposed.