I have installed a sani-flow macerator in a basement bathroom of a house I am flipping. Per the manufacturer instructions I have run one inch pvc to the sewer line from the macerator. I still need to vent it but running to the stack is not practical. Can I use a AAV/studor vent coming directly off the macerator vent opening? The opening is only 1 1/2 inches. I figure a studor will not work for a traditional toilet since more airflow is probably needed than a AAV will provide. But since this water is flushed into a macerator then pumped out and the vent hole is only 1 1/2 inches I figure I may be able to use an AAV? If so, can I just place the AAV right above the macerator or does it need to be behind a wall or something. Never used one. Any advice would be greatly appreciated as this house is u/c and buyers are annoying.

Thanks

As per the instructions, an AAV won't work on positive pressures. Usually, a vent can be run thru the block wall or out the bandboard.

So they are annoyed that the plumbing isn't done right? I would have already called in a plumber to do an inspection on the plumbing and furnace if I found telltale Diy signs.

I am not sure how the water flow works for a macerator, but if the bowl has a trap, then an AAV will prevent the water from flowing into the tank.

Professional Plumbing is both and artform and science based on plumbing rules and laws. Whe DYI'ers, do their best and the results are less than best, only then can we appreciate the art and science behind the finished project.

If you can't install the macerator per the manufacturers instructions, you should consider professional intervention. That would be a professional, licensed plumber.

Best Wishes