This is my current plumbing under my kitchen sink:
As you can see I installed an OS&B ABS Air Admittance Valve above the sanitary tee, I installed it to get rid of the "glugging" effect when draining the sink or when the dish washer was on. I followed the supplied instructions for installation, and everything has been working fine until last night.
I'm now experiencing an airlock, which won't allow any flow out of the trap. The water backs up into the other sink drain. At first I thought I had an issue with blockage, so I ran my snake 20' without any obstructions. I then removed the AAV from the stack and the sinks drained normally. The valve is functional, it opens and closes and no glue got inside of it.
Why am I getting an airlock with the current setup I have?