I'm getting some conflicting advice about the best way to join a tub drain to the main stack.
The book Remodel Plumbing (Rex Cauldwell) warns against using anything but a sanitary T-fitting when joining a sink to a vertical drain/vent because having a fitting with too much sweep will cause a siphoning effect. I'm wondering if the same principle applies when joining a 1-1/2" tub drain to a 4" vent stack (the P-trap is about 5 feet from the stack)
I'm joining a bathtub drain to a main stack and can't make the connection anywhere near level to the P-trap. I need a drop of about 10". Going by the book, I'm thinking that this configuration would work:
...but I've also been told that this setup with a Y and short 45 would work perfectly fine:
Any informed opinions?