Can I install an AAV here?

[broncoboy7]

I've started a kitchen remodel, and was not planning on doing any plumbing work. However, surprises are always hiding and when I removed the soffit in the old kitchen, I found a bunch of plumbing below the ceiling which was hidden by the soffit. I'm OK putting up a new soffit to cover most of the plumbing, but there's a pipe right in the way of where I was going to hang the range hood (using an existing vent to the outside).

I attached a picture of the plumbing layout. I want to remove the red section of pipe and install an AAV in the basement wall above where the washing machine drains. It seems logical to me, as gas still has a way to exit the system, but wanted to check with others and see if it makes sense!

Thanks for the help.

 

[snoop168]

Aav does not allow gas to exit. It only allows air to enter the pipe when there is a suction inside the pipe. It's sort of like when you stick a straw in water, theb pull it out... the water stays in the straw as long as your finger is held on the end. The Aav is like an automatic valve that takes your finger off the end of the straw when necessary. I'm not a plumber so not really sure if you could remove the vent pipe. I think I would say to make absolutely sure that it is only a vent and there is nothing else above draining into it from above, which it seems like you've already done so that's probably not an issue... if it were me and I wasn't sure I'd probably cut it at some point, install the Aav then test it out. Test everything including other fixtures in the house. If everything is good then you're probably safe to leave as is, if not just reinstall a coupling and put it back the way it was. Maybe a plumber could give you a better answer as I know that's ultimately what you're looking for....

 

[frodo]

from your drawing, you can do as you propose.

be sure to cap the pipe in the ceiling

install the aav. above the washer.

 

[broncoboy7]

Thanks for the replies!

I like the idea of doing a small cut right above where the AAV is going to go and checking nothing drains down that pipe. I'm 99% sure it's a vent only, but it's an easy test to make sure!

I'll definitely cap the end once I remove the full section of pipe.