Replacing Kitchen Sink Drain Line

We had to rebuild the foundation and floor under our kitchen and disconnected the existing plumbing to do the work. Below is a picture of the stud wall with the disconnected plumbing. I inserted some fittings showing how the plumbing was previously connected.



We decided to move the kitchen sink location a little to the right and would like to move the Y connection for the kitchen sink from the vent pipe on the left to the 2†drain line from the washer on the second floor located on the right. See picture below showing the new unconnected arrangement.



I have the following questions:

Is it permitted to tie the Y connection from the kitchen sink directly into the 2†drain line from the washer on the second floor?

Is it better to use a 1-1/2†or 2†trap for the kitchen sink?

Thank you for taking the time to read my post and consider my questions.

Howard

The first picture is correct except use a 2"x1½"x1½"sanitary tee instead. The trap needs to be 1½" as well. The following is from the Illinois plumbing code.

Trap Size. The size of trap for a fixture shall comply with Appendix A: Table E for minimum size of traps. No trap shall be larger than the fixture drain to which it is connected or the drainage pipe into which it discharges.

Appendix A: Table E

Fixture_____________________DFU__________Trap Size
Kitchen sink, domestic ------------ 2----------------- 1½"

Thank you or your comments. So tying the sink drain line into the 2†washer drain line is not permitted. You are also recommending we stay with a 1-1/2†drain for the sink and trap. How about using 2†to 1-1/2†reducers to connect the 2â€x2â€x2†long radius Y in the pictures to the 1-1/2†vent line and 1-1/2†trap from the sink? I believe this arrangement would be less likely to clog.

It would have been nice to have moved the Y for the sink drain over to the right since the sink and its drain are also moving to the right. Now the Y connection will have to exit the sheet rock at an extreme angle to the right to make a connection to the sink.

One more question. Are there general guidelines on how high the horizontal 1-1/2†drain line that exits the wall and connects to the kitchen sink trap should be from the floor? We don’t have the sink and model of disposal pinned down yet and we don’t want to put the connection to the 2†drain line in to high or low.

Thanks !!

You might want to figure out how deep a sink your using and a disposer...
You can work out some big differences there...
Undermount 2 basin deep sink with batch feed disposer vs. a drop in single basin shallow sink with an evolution compact could easily be a 1' difference in height...

I would suggest looking at the InSinkerator Evolution line...
IMHO There are the end result of decades worth of development...

http://www.insinkerator.com/excel/grind_more_hear_less.shtml

drain

It is easy to put it too high, but difficult to put it too low unless it is right down by the bottom of the cabinet.