Question:
I’m setting up a 2″ drain in front of the dishwasher and disposal outlet. Due to other plumbing and HVAC obstructions, I can’t move either of these fixtures. I also need to install an air admittance valve (AAV) and a garbage disposal. I’m unsure which layout is best: the first setup with a bunch of 45-degree angles, a sanT, and the AAV high in the back left, or the second setup with just a couple of 45s and a T for the AAV along the horizontal? I can’t place the AAV in the back right corner because there’s a soap dispenser. Any suggestions?
Answer:
In this situation, the second option with a couple of 45s and a T for the AAV along the horizontal is likely your best bet. Here’s why:
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Simplicity: The fewer bends and fittings you use, the better. Extra angles can cause flow restrictions, leading to clogs and less efficient drainage.
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Accessibility: Keeping the AAV along the horizontal makes it more accessible for future maintenance and adjustments. It also reduces the risk of clogging or blockage from bends.
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Efficiency: Plumbing with fewer components often works more efficiently, and you’ll avoid unnecessary complexity.
The first setup, while functional, uses a more complicated arrangement with more potential for flow restriction due to the numerous 45-degree angles. Also, the placement of the AAV high in the back left could create potential issues with water flow and accessibility.
In this case, simplifying your layout with just the necessary components and positioning the AAV horizontally will result in a cleaner and more effective system.
For more tips on drain layout and proper installation, visit Plumbing 101.
I’m Chris Mayer, writing for Plumbing 101.
