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Install Vanity Drain Lines — Mark the Cut Location

Beginner

Part of project

How to Install an Air Admittance Valve (AAV) · Step 2 of 7

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In this video

From the newly installed combi-y, run a new horizontal ABS drain pipe under the floor. Use a 90-degree elbow to direct the pipe vertically up into the wall cavity. In the wall, install a sanitary tee fitting on this vertical pipe. Then, extend two horizontal drain arms from the tee, one to the left and one to the right, to create the stub-outs for each of the two sinks.

Goal: Run drain lines for two sinks

Used in this video

  • Pipe CutterCutting ABS pipes to length.
  • LevelEnsuring the horizontal drain arms have the correct downward slope.
  • Measuring TapeMeasuring pipe lengths.
2.0K views31-1.5 hours
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FAQs

What are the most important safety precautions I should take when installing an AAV?

Always wear appropriate personal protective equipment, including safety glasses and gloves, especially when cutting PVC pipe and handling chemical solvents. Ensure the work area is well-ventilated when using PVC primer and cement to avoid inhaling fumes. Have a bucket ready to catch any residual water from the drain line.

Do I really need all those specific pipe cutters and deburring tools for this project, or can I use a simpler tool?

While a hacksaw can cut PVC, specialized pipe cutters (like the ratcheting PVC cutter or plastic tubing cutter) provide much cleaner, straighter cuts with less effort, which is crucial for a tight seal. A deburring tool is also highly recommended to smooth edges, preventing snags and ensuring the best bond with primer and cement.

How long does a typical AAV installation take for a beginner, and what's the estimated cost of materials?

For a beginner, this project typically takes 1 to 3 hours, depending on preparation and experience with plumbing. The material costs, including the AAV, PVC fittings, primer, and cement, usually range from $30-$60, assuming you already have basic tools like a tape measure and bucket.

Where is the ideal location to install an AAV on a sink drain line for optimal performance and code compliance?

The AAV must be installed vertically, at least 4 inches above the horizontal drainpipe it serves, and critically, above the fixture's flood level rim. This prevents water from entering the valve and ensures proper air intake, while complying with most plumbing codes.

Transcript
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to come off that, run it up the wall there, tee off, go in both ways, and then I was able to run it up and then out and up and out. And then with the water lines, here

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