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Under sink plumbing vent- what is it for?


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04-20-17, 07:48 PM   #1 (permalink)  
Under sink plumbing vent- what is it for?

I was replacing my faucet today and noticed this white thing with vent holes. What is this for. It looks attached to the main drain and if the main drain ever backs up, water may come flying out of these vents. Any help or recommendations would be appreciated..

Thanks!

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Last edited by PJmax; 04-20-17 at 07:51 PM. Reason: reoriented picture
 
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04-20-17, 07:56 PM   #2 (permalink)  
That's called a Studor vent....... or an air admittance valve.
It's there to take the place of the rooftop vent line.

It's basically a one-way valve. It allows air in and keeps "stuff" in the pipe from coming out.
Many times they are mounted in the top of the countertop so that no "stuff" could leak back.

At the least..... it should be installed high up inside the cabinet.
If your drain line was clogged..... that valve could leak.


~ Pete ~


Last edited by PJmax; 04-20-17 at 08:12 PM. Reason: typo
 
garywi's Avatar
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04-20-17, 08:02 PM   #3 (permalink)  
Thanks. So you think I should raise the height of it somehow?

 
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04-20-17, 08:13 PM   #4 (permalink)  
Personally.... I'd like to see it higher.


~ Pete ~

 
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04-21-17, 03:40 AM   #5 (permalink)  
I agree with Pete, it should be higher than the bottom of the drain. It doesn't matter if you have to reconfigure it to one side or the other, since all that is in the pipe is air, but it will leak that low should you have a stoppage.

 
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04-21-17, 04:12 AM   #6 (permalink)  
I was told by an inspector that there are to be no elbows in a AAV piping. I didn't question why, just complied with his request.

 
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04-21-17, 04:34 AM   #7 (permalink)  
Just another observation; but if that flexible stainless pipe is servicing the Sprayer up above in a kitchen sink, I'd be concerned about it, through usage, slowly unscrewing the plastic nut at the bottom of the AAV.

Watch it in operation, and see if the pipe can be re-routed if necessary.

 
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04-21-17, 08:57 AM   #8 (permalink)  
I think your AAV is OK the way it is. The AAV you have is a one piece unit as far as the pipe goes and was designed for that height.
There's no harm in raising it, but I wouldn't bother.

Here's the general guidelines:

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Brian

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