Crown Vent (determination)

[Hamberg]

From what I've learned (here), the trap arm needs to be 1.5x the (largest??) trap diameter. If the tail pipe (1.25") piece dumps into a 1.5" p-trap, the trap arm would need to be at "least" 3", beginning at the trap weir?

Question is, does that 3" need to be exposed? (in other words if the trap weir begins, near or at, the back of the vanity and extends 3"+ into the wall cavity, is that to "code"

 

[Twowaxhack]

Crown vent means the trap weir is connected too close to the vent.

You’re not near the vent in your pic, or if you are, it’s fine. You’re atleast two pipe diameters away from the vent

Nothing has to be exposed.

 

[MrInfoPhilly]

From what I've learned (here), the trap arm needs to be 1.5x the (largest??) trap diameter. If the tail pipe (1.25") piece dumps into a 1.5" p-trap, the trap arm would need to be at "least" 3", beginning at the trap weir?

Question is, does that 3" need to be exposed? (in other words if the trap weir begins, near or at, the back of the vanity and extends 3"+ into the wall cavity, is that to "code"

View attachment 33322

yeah., as Two said., Trap arm is the distance., 2x the pipe diameter is the min length., you're Fine as it is., you have at least 3 inches so you're good...
Your wife may complain though

 

[Hamberg]

Keep telling my wife: 3" is the new 12!

Am getting ready to rehab that bath, embarrassing what the last GC did to it! Seriously doubt the venting is correct but will find out once apart.