Thursday, February 9, 2012

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PEX Plumbing Installation


Before you buy your PEX plumbing supplies, draw up your intended layout. As you plan your layout, remember that because of its flexibility, PEX allows for designs that are just not possible with traditional rigid pipe. For example, PEX tubing can be pulled through holes drilled in your floor joists, keeping your pipes tucked neatly up into the floor frame and out of the way. Note the locations and types of any fittings you're going to need, taking into consideration any major obstacles you may encounter in the framing.


To get started you'll need;

  • 90° Angle drill
  • 1-1/4" - 1-1/2" Spade bit
  • PEX Pipe
  • PEX Fittings
  • PEX Crimp rings
  • PEX Cutting tool
  • PEX Hangers
  • Metal stud plates
  • Expansion tank

Note; before you begin, make sure that your project complies with local code and that you've acquired any necessary permits.

If you encounter a problem while installing PEX, just Ask Our Plumber.

Installation:

1. Drill holes in the studs or joists where you plan to run the PEX pipe. Apply metal stud plates where the holes have been drilled to prevent screws and nails from accidentally puncturing the PEX pipe and any other vulnerable pipes. Pipes and wires can be hit easily when drywall and moldings are installed. Tip; you can reduce the need for metal plates by drilling your holes high enough in the joists that a nail or screw can’t reach them.

2. Feed the pipe through your drilled holes while someone else is pulling it from the coil. Keep in mind that PEX tubing is very flexible and it expands and contract as it heats and cools. This is more common on the hot side because, as the hot water travels through, the pipe heats up rather quickly. To prevent too much linear expansion in vertical runs you can make a loop or a u - bend up inside the floor joist. You can also reduce linear expansion by adding a piece of copper in every fifty feet of PEX. For all domestic water systems with storage type or on-demand hot water tanks we recommend an expansion tank. When water is heated it expands, creating additional pressure on the system. The expansion tank has a bladder inside that helps take that expansion out of the system. This also reduces pipe noise and prevents your relief vents from blowing off.

3. Use PEX hangers to secure the pipe to studs or joists and near any bends to reduce the strain on fittings. Be sure to use hangers made of plastic and are made for use with PEX. Some hangers made of metal were not intended for use on PEX or copper. Use a hanger every 32” on a horizontal run. On vertical runs the pipe will need support at every floor level. Apply the supports firmly, but do no tighten them around the pipe to allow for pipe movement.

4. Apply your fittings by sliding a crimp ring over the pipe. A good square cut on the end of the PEX pipe is essential before you insert any fittings into it. Be sure that the pipe butts the fitting shoulder. Slide the crimp ring over the end of the pipe leaving 1/8” – ¼” of the pipe exposed. Use the crimping tool to crimp the ring tightly into place.

5. Once all of your pipe is installed in this fashion turn the main water supply on and check for any leaks in the joints. Redo any leaking joints and test again. If you’re working on a new build you can also do a leak check with an air test. Just put an air gauge in line with your system. Pump it up with air and watch to see if pressure drops on your gauge. We recommend leaving air in the system for at least two hours and check your gauge for a pressure drop. Tip; if the pressure does drop you can make a solution of liquid soap and water. Apply this solution to your fittings; if they blow bubbles then that connection is leaking.