Yes, the exhaust line could be tied into the vent line. In fact, thatâ€™s the way I had shown it on my original drawings when I had applied for the provisional patent. However, I felt that there would be the possibility of odors reentering the occupied space in the event the back draft damper failed. Also did not want to create any possible code issues due to having a positive air displacement condition. The separate line takes out all doubt. As far as an additional hole, this is not a problem as there are several roof penetrations on any given house or building already. If in doubt about the install, hire a professional to do the work.
If you would have read the site in full, you would have seen that the U.T.A.'s trap is maintained with a trap primer built into the toilet as explained in the "How it works section" on the flushing operation link. Each time the toilet is flushed a small amount of water supplied to the trap. Or in commercial applications as were the fan is likely to run in contiguous mode, a remote trap primer would be used. I will include some more information on the site referring to set up and what to do in the event of an overflow later.
As far as all that plumbing", the U.T.A. is a one piece unit therefore guaranteeing it to perform as claimed and making the install simple. The site is still under construction and I intend on having more information up so that everyone understands it better.
In renovation conation, it is recommended to let a professional do the install. New construction would be simpler of course. A product such as the VIP would be a simpler install. Not product bashing here but if you feel that any given product that has one feature (odor control) and not two (odor and overflow control) is "superior", that is your opinion and I can certainly appreciate it. I am familiar with the local codes in Ga. and feel that there are no issues.
Thank you for your comments as they help me to better design my site so that everyone understands it better. As most inventors probably realize, itâ€™s hard to get other to see whatâ€™s in your thoughts sometimes.