Connecting 2" shower to 3" Toilet Pipe?

[thetoolsmith]

I'm trying to plan out my new plumbing to connect a wall hung toilet to and existing 2" drain and vent. In the image below the new wall hung toilet is covered in black plastic to help keep things clean. The old 3 inch drain is in the left bay and turns vertical down through a 2x4 supporting wall near the new toilet. This old 3" plumbing can be removed (hopefully)


I've sketched out what I hope will work using a 3x3x3x2 Hub Sanitary Tee with 90 Left Inlet to connect the revamped 2" drain/vent to the new 3" drain. I'm assuming I can cap the top 3" opening if this setup works. Does this setup look like it will work?



Thanks for any feedback

 

[thetoolsmith]

Another idea I had is instead of using a 3x3x3x2 Hub, is using a Double 90 Hub with a 3 to 2 reducer to pick up the 2"drain. What are your thoughts about this?

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[MicEd69]

You cannot reduce the size of a drain line going downstream for any drains, especially from a toilet.

 

[thetoolsmith]

You cannot reduce the size of a drain line going downstream for any drains, especially from a toilet.

Agreed, the reduction would be on the 2" drain side for the shower / vent

 

[MicEd69]

Oops, I'm doing things too fast today. I misread your title thinking you were wanting to pipe a 3" toilet into a 2" shower drain. LOL.

The fitting you have labeled as a 2" Sanitary tee in the middle of your sketch needs to be a combo fitting or a wye with a 45 fitting. It would also be best if it were rolled up at a 45-degree angle. That existing drain and vent would wet vent the shower and toilet in reality. This design works and would be OK in an IPC code area, but maybe not if you are under UPC. They are more restrictive when it comes to venting a toilet.