Flush shower drain two ways?

[John E G]

I really appreciate this forum, first-time poster, hope this is the right place.

I demo'd a shower & tub to expand the shower.
Planning a curbless shower with a trench drain, and I'm sensitive to draining.
Questions are: Does it make sense to try to drain to both the old 2" shower drain and the 1½" tub drain?
Does this help, is it stupid, or good insurance? Is the venting proper?

Any other advice would be appreciated.

 

[wwhitney]

That would be highly . . . non-standard. I don't see the upside. Just run a single 2" drain from the trap to the right to a san-tee near the drain and vent.

Cheers, Wayne

 

[Sponsor]

 

[John E G]

Thank you Wayne!