I thought I'd pass along my findings and my fix....
For those who experience sewer smell in their bathroom after having run the Max Air ceiling exhaust fan and you do not have an air admittance valve under your bathroom sink, but instead have an actual sewer vent pipe that your sink drains into... your issue may be what ours was.
Your vent pipe is probably not sealed between itself and the roof. When you turn on the exhaust fan, it sucks the gas from the vent down into the wall behind the sink, and through the wall where your sink drain enters into your sink base cabinet.
As part of my search for a solution... I turned the fan on full, went up on the roof, removed the vent cover's cap, and applied smoke around the area. Sure enough, the smoke was drawn down into the rig around the outside of the vent pipe.
I made a crude CAD model to illustrate. I sealed the gap on all three of our vents, and no more smell!
Hope this helps someone ...
-David
Linear Mode
