We would like to see a diagram on how to plumb a 3 bowl kitchen sink. The drain pipe enters through the floor, not the back. The air vent is on the drain pipe that goes through the floor. The drain in the center sink sits ahead of the left and right drains. We using standard pvc pipe and connectors. The drain pipe in the floor sits slightlty ahead and to the right of the drain in the right bowl. The current set up we just put in is not draining properly and water backs up into all the sinks. Any suggestions? Do you have any diagrams to help show us how 3 bowl sinks are plumbed?

Any chance of a picture? If the drain goes through the floor you probably have an S-trap. Who did your recent work, you may want to bring them back and ask if a S-trap meets your local building code.