Could someone please review the attached sketch of how I would like to plumb my basement bathroom? The only existing lines in the drawing is the 4" building drain that runs from the exterior wall of my home to a tee where a 3" drain runs toward a 3" stack that feeds an upstairs bathroom and a line that I believe is 3" that serves the kitchen upstairs and a floor drain that was removed.
I would like to tie into the 3" line below the floor and put in a double wye, one side for a floor drain and the other side serving the rest of the bathroom group. The 3" will run all the way to a toilet and will have a wye that runs to 2" to serve the shower and bathtub. A 2" vent (maybe this could be 1 1/2" now that I look at it) will serve a sink. On the other side of the room, I plan to remove an existing floor floor drain to to connect to the existing wye that is already in the 4" main service line and install a new 3" floor drain (that will be near the laundry machine and utility sink in case the hoses fail at any time) and a 2" vent that will serve as the drain for the washing machine and the utility sink. This will be vented with a 2" lihne that will connect back with the shower vent and the sink vent into an AAV near a point where I can run the vent through the upstairs wall in a future project.
Please look at my drawing and give me any comments or suggestions. My particular concern is using the vent as a drain line for the washing machine and the utility sink. Could anyone give me a recommendation as to whether I need to use a studor "maxi vent" rather than a "mini vent"? The sizing information on the specification sheet was confusing to me in that it had maximum dfus for branch and maximum dfus for stack.
Thanks for your help.