How to Work With CPVC Pipe

If you've ever done any plumbing work with copper or galvanized pipe, you are in for a treat. CPVC plastic pipes are lightweight, easy to cut and a snap to put together. They also require only a minimum of tools and, in most localities, are approved for both hot and cold water in residential use. CPVC pipes can carry water up to 180 degrees F at a pressure of 100 pounds per square inch (psi): the standard home uses water no hotter than about 125 degrees and a pressure of approximately 50 psi. CPVC can be distinguished from its cousin, PVC, by its beige color (as opposed to the bright white of PVC). PVC can be used for drains and underground plumbing, but CPVC should be used for interior plumbing that will carry both hot and cold water under pressure. CPVC pipe can be purchased in 10-foot lengths at any hardware or home center store in 1/2 or 3/4 inch diameter.

Things You'll Need

• CPCV cutting tool or hacksaw
• 100-grit sandpaper
• CPVC pipe
• CPVC fittings with mechanical grips
• CPVC nonmechanical couplings
• CPCV solvent
• CPVC glue

Instructions

1. Shut off the water to your home at the main shut-off valve. This valve is usually at the front of the home where the main water line enters the house. It is usually a wagon-wheel valve; turn it clockwise until the water stops flowing.

2. Open one or more faucets in your home to allow the water to drain out of your system. Unlike copper or galvanized pipes, it is not necessary for all water to be out of your pipes in order to plumb with CPVC.

3. Layout your plumbing project to use the least amount of CPVC pipe and the fewest number of connectors.

4. Measure the length of your first piece of CPVC pipe. Be sure to consider that the connector will add approximately 1 1/2 inches to the length of your pipe. Cut the pipe with a special CPVC pipe cutter (which will cut straight and leave no plastic burrs on the end of your pipe) or cut your pipe with a hacksaw. If cutting with a hacksaw, use your 100-grit sandpaper to smooth any plastic burrs off of the cut end. Use your 100-grit sandpaper to rough up the end of the pipe that will slip into the coupler.

5. Spread primer onto the end of the pipe and the inside of the coupler with the brush that comes with the primer can.

6. Spread cement onto the cut end of the pipe and the inside of the coupler with the brush that comes on the cap of the glue. Make sure the glue is still wet when you shove the pipe and coupler together. Turn the pipe or coupler 1/4 turn if possible to help spread the glue. Allow the pipe and the coupler to dry for 1 hour before running water through the system.

7. Shove a mechanical plastic coupler nut onto the end of a pipe that will be mating with the threaded end of a piece of CPVC pipe. The mechanical nut has an O-ring to help make the coupling watertight; shove the coupling nut onto the pipe so that the pipe has gone past the O-ring.

8. Align the two ends of the pipe and tighten the plastic nut onto the threads by hand. Do not use a wrench to tighten. No primer or glue is necessary for a mechanical connection. Mechanical connections can be tested for leaks by running water through the system immediately.

9. Open the wagon wheel water shut-off valve to return the flow of water to your house. After the air is forced out of the lines and water begins flowing from the faucets you opened in Step 2, shut off the faucets and check all connections for leaks.

Tips & Warnings

• CPVC pipe can be connected to copper pipe using the mechanical plastic nuts following the directions in Steps 7 and 8.

• CPVC pipes and nonmechanical connectors must be joined quickly after the cement has been applied; the cement melts the plastic of both the pipe and the connector, so when they are shoved together they bond as if there were one piece of plastic.

References

• How to Use CPVC Plastic Plumbing Pipe