Finding Sink Vent

[AlGreen]

In another thread, I noted that a plumber who checked out the gurgling in my second floor bathroom sink said he didn't think it was vented. He didn't use a camera, but instead stuck a screw driver in the space around where the drain pipe enters the wall (inside the vanity) and felt for a vent pipe branching off. He didn't feel anything and came to his conclusion.

Now before I go ahead and try to somehow hook up an AAV to the horizontal pipe after the P trap, is there any way to confirm that the sink is unvented - besides having amother plumber come in with a camera?

 

[hj]

Feel inside the opening. IF the pipe turns down, there is no vent, if it turns sideways there probably is a vent but no way to tell for sure. The pipe may be to small for a camera to be inserted.

 

[Sponsor]

 

[JohnjH2o1]

If you can feel the pipe turning down in the wall with a 90 and not a tee then it's not vented. If it is turning horizontal then there is a good chance it is vented.

 

[JohnjH2o1]

hj beat my post by two minutes.

 

[AlGreen]

Thanks. Best I can tell by feeling with a screwdriver, the pipe takes an immediate 90 degree turn down. So no venting.

Can an AAV even be installed in the space I have, which is only about 3 inches from the P trap to the wall?

 

[Terry]

To make room for an AAV, you would 45 out from the all, add a tee, and then come back and pick up the lav.

 

[AlGreen]

To make room for an AAV, you would 45 out from the all, add a tee, and then come back and pick up the lav.

Thanks Terry. So pick up a 45 degree elbow to attach to the wall, add a sanitary tee to that for the AAV, and then another elbow to hook back to the P trap? Trying to make sure I'm visualizing this correctly.

 

[Terry]

Something like that. The p-trap has some swing to it though.
I would use street 45's to reduce the length of the fittings.

Something I saw in a restaurant bathroom.

Question, is it galvanized pipe coming out of the wall on yours? That might makes things more interesting. If it's 1-1/4 the fittings are a little harder to come by. And you will need to thread on there somehow.

 

[AlGreen]

It's a circa 1926 home, so I'm guessing it is galvanized, though I don't know the size. A fitting of some kind is currently threaded in there. Hmmm...

 

[Terry]

It's a circa 1926 home, so I'm guessing it is galvanized, though I don't know the size. A fitting of some kind is currently threaded in there. Hmmm...

It may be 1-1/4" if it's a lav drain. It looks like someone spun a new pipe nipple in there recently.

 

[AlGreen]

So I need to try and find a 1 1/4" street 45 for the wall side.