Air admittance valve question

[mikejurasw]

Hi everyone,
I'm working on a "tart-up" of our master bath (full gut job is out of the question).
At any rate, I'd like to relocate a vent pipe for the tub/shower drain. It travels from the base of the tub up to the ceiling, makes a couple turns and then was cut off and buried in the wall of a third floor closet. It hasn't communicated with the outside for 15yrs! The guy who flipped this house just disconnected it from the roof vent and hid it.
So, can I either: 1) cut it somewhere that fits my re-model, transition to pvc, and then install an AAV in the wall/ceiling space?
or 2). just chop it off a little above the flood line of the tub and install the AAV right there behind the future access panel?
Currently it looks to be 2 inch steel.
Thanks!
Mike M
Cleveland, OH

 

[havasu]

AAV's are prohibited in many areas. Why not just do it the right way and extend it through the roof?

 

[Fireguy5674]

If you need to relocate, cut it off below the floor, adapt it to PVC and run it where it is out of your way. Then like havasu says tie it back into the main vent stack or vent it out the roof independently. If you need to run horizontally very far make sure you maintain the 2" size.