I have a VERY slow drain in my kitchen sink. So slow that water has backed into my dishwasher through my garbage disposal. After a long time the drain finally goes down. Liquid Plumbr didn't seem to help.

I have an AAV under my sink, and when I unscrew this the sink seems to drain quicker. Not sure how quick, exactly, since water was backed up the straight pipe to the valve and dripped down into the cabinet. The AAV has only been installed for 4-5 months. Could this be the problem, or is it more likely a clog?

Thanks.

I would be more inclined to think the horizontal drain in the wall has a partial clog. However, If the sink drains better with the AAV removed I would replace what you have with a Studor AAV. If you still have a problem then snake the lineRemove the trap and send a snake up into the wall. You will hit a elbo about 8 inches in but work your way around that and you'll only have 6 more feet to go. Flush the line after you're through with a tub full of hot water.. good luck, Tom

Thanks Speedball. It turns out there was a clog right at an elbow, like you said. I had to go back through the clean out valve to clear it. The AAV was OK.