Mistake : Wye instead of Tee for washroom sink drain

[naimc]

Continuing on my washroom reno, from previous thread : https://terrylove.com/forums/index....-sink-tie-in-to-show-drain.107247/post-763794

At the point where the 2" drain meets the vent in 1-1/2" I used a Wye for the sink drain. I was distracted by vent routing and fail on this basic joint.

Now thinking of the sheet rock that will go up I realize that I should have use a 90 degree Tee correct ? as the wye would not allow proper venting because of the 45 degree angle ?

Part I should use ?

 

[Tuttles Revenge]

Correct, that should be a San Tee to comply with code for venting a trap arm.

 

[Sponsor]

 

[wwhitney]

Definitely best to swap out for a san-tee.

However, as the trap arm is so short, the wye might possibly comply with the trap weir rule. Basically, the question is this: as a thought exercise, if you were to plug the vertical drain just below the wye, and slowly added water above the plug, which would happen first: (a) the water level hits the "crotch" of the wye, cutting off air communication between the top entry and the side entry of the wye or (b) the water spills over into the u-bend of the trap.

If (a) would happen first, then you definitely need to change it to a san-tee, as that creates the conditions for siphoning the trap. If (b) would happen first, you should still change it to a san-tee, but depending on the details of the Canadian Plumbing Code, it may or may not be a violation as is.

Cheers, Wayne