Could an alternate air admittance valve work here?

[breadtoaster]

Hi Plumbing team,

My apartment was recently renovated and we have some terribly smells from the shower drain. A plumber quoted us at installing a new air vent, however I tried my best to learn more about plumbing and came across an Air Admittance Valve. The mechanical system, with the occasional replacement if it fails, is fine with me.

I have drawn up the stack and would like to install an AAV at the toilet as this is the drywall, which would be easier to open rather than tiles.

- Where should I place the AAV? Would an AAV at the toilet more likely fix the issues? Instead of installing the AAV at the shower?
- If there is a toilet sink before reaching the shower, would we also expect smells at the toilet room sink?
- What are your general thoughts on AAVs?

Thank you in advance, happy to provide more pictures of the situation.

 

[MicEd69]

You really need to show the actual drain and vent piping and dimensions. For the smell to come up from the shower drain, the shower either doesn't have a P-trap (unlikely), or the flow from the toilet is siphoning out the shower P-trap (possible), or the shower drain connection to the drain branch is incorrect (possible) allowing sewage flow from the toilet to enter the shower drain line and into the shower drain line/P-trap.

If the toilet flow is siphoning the shower P-trap, the new vent, or AAV, need to be on the shower drain. And the AAV much be accessible behind an access panel or exposed. They cannot be installed and inside a wall with no access.