Do I need air admittance valve?
#1
07-31-17, 09:33 PM
Do I need air admittance valve?
I was told to install a sink drain vent pipe system called "abs in-line vent" on the red box. He said that flushing the toilet might empty my drain trap, however my drain trap is doing fine after I flush. Do u think I need to install it?
#3
08-01-17, 12:07 AM
Group Moderator
He said that flushing the toilet might empty my drain trap
An air admittance valve is like the path of last resort. Your plumbing system is supposed to have vent lines in the wall and up thru the roof.
#4
08-01-17, 12:36 AM
An employee at Home Depot, he's a licensed plumber. BTW how do u reply with quote on this forum?
#6
08-01-17, 11:14 AM
Current code (US) requires venting for all fixtures. In this case, if it was a new install, it would need a vent, either direct vent to the outside or an AAV.
Considering this has been here for a while and you're not seeing issues, I don't know that I'd go through the hassle of replacing all of it just to add an AAV. Up until the '70s or '80s, S-traps (like you have) were quite common. There are a LOT of them still around, mostly not causing big problems.
If it was a new installation, I'd definitely push to correctly venting. It's really up to you whether you want to add the AAV since it's likely grandfathered in code-wise.
Considering this has been here for a while and you're not seeing issues, I don't know that I'd go through the hassle of replacing all of it just to add an AAV. Up until the '70s or '80s, S-traps (like you have) were quite common. There are a LOT of them still around, mostly not causing big problems.
If it was a new installation, I'd definitely push to correctly venting. It's really up to you whether you want to add the AAV since it's likely grandfathered in code-wise.
