I have a kitchen sink on a peninsula so 3 years ago, when I installed it, I used a vent valve. It is installed with the vent about 12" above where the trap enters the larger main drain.
It has worked well for 3 years. Put the drain started slowing down noticeably a few weeks ago. Plunger did the job. But slow down events got closer and closer until the plunger did not clear them.
So, after washing dishes we had a sink full of awful water. I pulled the vent valve and the water was practically sucked from the sink. So I bought a brand new Oatley valve, installed it and we are back to the slow drain.
Pulled the vent valve again. As it loosens you can hear the air suck past the threads with some force and the sink drains. But the valve back on and the drain stops again.
Could I have bought a bad valve? Seems like an awful coincidence. Any other thoughts?
I just tested the new valve by blowing into it and sucking air out, it works as it should.
Edited by TWLack (04/19/18 08:22 AM)