Any suggestions or insights on this problem would be much appreciated.

Kitchen remodel moved double sink with disposal and passive air vent to a single large sink with disposal and a minivent. Now water won't drain through disposal unless it's turned on. Contractor thinks it's a plug in the drain line and plans to snake the line Monday. But all other drains in the house work fine, and this one works fine -- but only if the disposal is running. I've read on this forum that this problem could be caused by a nonfunctioning AAV (link to that thread is at bottom of this message). There's a Studor minivent in place now, as shown in the photo below.




Link to thread on this forum titled "Studor minivent does not work"
[www.plbg.com]

The problem is that the sink is "air bound", maybe because of a stoppage, and the Studor is completely useless to relieve it. The fact that the disposer can push through the air bound drain, however, implies that it is more serious than a simple stoppage, because that would also prevent drainage when the disposer was operated.

If the AAV can unscrew, take it out and see if the sink will drain properly. If it does, you know you need an atmospheric vent.

This seems likely. My wife and I think that the sink was draining fine the first time we used it, but we found water in the cabinet and on the floor so we stopped using it. The contractor had forgotten he had not yet capped that vent pipe with the minivent. From the time he installed the minivent, we think, we've had the no-drain-without-disposal-operating problem. We'll have him test the drain with the minivent removed.

If it needs an atmospheric vent, could that be as simple as running a pipe through the back wall of the cabinet--and then through some insulation and siding--to vent directly to the outside? That wall of the kitchen is a popout with just some framing, insulation, and siding.

Thanks to you and hj for such quick and helpful replies!

This problem got me to looking at various manuals for the products involved, and I discovered that the drain hose of the dishwasher should be installed with a portion at least 20" off the cabinet floor. I guess even I could manage to do that.

That has nothing to do with your problem, and an atmospheric vent might just eliminate the symptoms without addressing the real problem, which is why it does not drain with the AAV installed.

Yes, get the dishwasher drain hose as high as it can possibly go and secure it in that position.

Just closing the loop on this. The problem was a partially clogged, very old metal drain pipe. Snaking it and then replacing a big piece of it solved the problem.