Thread: plumbers... kitchen dbl sink in island.... mechanical vent?

I plumbed my own kitchen double sink and its a new home so the inspector was out when i wasnt there and the whole house passed code except the stupid sink drains. he only left one comment on the paper that said "kitchen sink drain- mechanical vent" ... so i put a tee in located after the ptrap just before the drain pipe exits down the floor.... on a horizontal piece of pipe.... then put a tall piece of abs on that pointing toward the counter. on top of that is a strange gizmo the local hardware store called a mechanical vent.

sooooo did i put it in the right location or should it have been inserted on the other side of the ptrap? the side closer to the sink basins??

Fixtures located a certain distance from the main stack need their own vent. If the sink is too far from the stack and the drain line you are using is dedicated to that sink and doesn't already have a vent line to the roof, then you need to add a vent line. You are fortunate to live in an area that allows the mechanical vents, as without that, you end up needing to vent through the roof which is a lot more work, especially for an island install.

Assuming you followed the correct geometry for a vent line, it sounds like you have interpreted the sheet correctly.

The side of the p-trap closest to the sink. BOCA vents (mechanical vents) are now allowed in all states due to universal acceptance of plumbing codes. If the vent is on the waste side of the trap your allowing sewer gases into the kitchen. Switch and your good.

mechanical vent is just a rubber stopper that lets air in when water is draining out .always needed with island sinks..it should be installed below the traps no more than 6 inches