Geniescience
Homeowner
more venting please
In your original post you asked whether you need an undersink vent. The answer is looking more and more like Yes by all standards.
You just mentioned "all the pipes shown", meaning all the white ones, or even the last one that is yellow - beige? Where does that one go once it goes through the floor? In your first post you said you weren't sure about venting in general, in your house. Is there any venting from anywhere else soon after that drain pipe goes through the floor?
If this drain is not well-vented soon after that S trap, it explains your slow kitchen sink drainage. Adding an AAV vent under the sink is a good way to add venting to your whole drain system, and to vent the (new) P trap replacing the S trap. An S trap once vented is no longer an S but now a P trap.
david
In your original post you asked whether you need an undersink vent. The answer is looking more and more like Yes by all standards.
You just mentioned "all the pipes shown", meaning all the white ones, or even the last one that is yellow - beige? Where does that one go once it goes through the floor? In your first post you said you weren't sure about venting in general, in your house. Is there any venting from anywhere else soon after that drain pipe goes through the floor?
If this drain is not well-vented soon after that S trap, it explains your slow kitchen sink drainage. Adding an AAV vent under the sink is a good way to add venting to your whole drain system, and to vent the (new) P trap replacing the S trap. An S trap once vented is no longer an S but now a P trap.
david