1st and 2nd floor kitchens -- how to plumb correctly

[tlw00dy]

Hi helpful and experienced plumbers.

I purchased a two-flat that has one kitchen above the other. The 2" stack goes from the basement on up through both kitchens and then through the attic and roof. Only the kitchen sinks are on this stack.

Each floor appears to be connected fine and according to code. However, when we put a significant amount of water down the 2nd floor kitchen sink, we get lots of gurgling and actual water pushing into the sink on the 1st floor.

Any thoughts what can be done to correct this?

Warm regards,
Tom

 

[tlw00dy]

My thought was to replace the sanitary tee connecting the 1st floor p trap to the stack with a wye. Will that solve my problem?

 

[Sponsor]

 

[tlw00dy]

OK, I just read that it's prohibited to use a wye in that application. So, I'm at a loss for ideas at this point.

 

[Reach4]

You should have had a separate vent line for the bottom kitchen.

You could compensate by adding an AAV for the bottom kitchen. The lack of a vent would not have cause that problem, however.

What you want to do is to get the drain line rodded or jetted out. The most likely place for build-up is where the drain transitions from vertical to horizontal. If you cannot get that rodded easily enough, get a cleanout added.

If you have garbage disposals, they are going to make the buildups faster.

I am not a plumber.

 

[Terry]

I would install an AAV on the lower sink and see if that helps. Santees on the vertical for a trap arm is the right way.
Though it would have been best to vent it, and bring that vent in above 42" on the second floor.