Hi GC peeps, Heres a situation, im hoping someone with a little HVAC experience or some ventilation knowledge might be able to help fix it. Situation is: 172cfm vortex fan, hooked to a carbon filter. The fan exhaust heads about 3 feet out of the room, and then joins in a home-made Y piece (made out of 3 sections of 4" exhaust hoses) joining the Y with it is a clothes dryer. They both shoot out the tail end of the Y another 10-15feet and exit the house via the "dryer vent". The fan runs 24x7, but the dryer only runs every so often. Since install, the dryer takes twice as long to dry any clothes. You can occasionally get a bud smell in the laundry room so im guessing some air is making its way back up. Is there any way I can fix this so both lines still run out the same hose, and the dryer doesnt take forever to dry? I thought about putting a damper behind the Y on the dryer side, but that would only stop air from coming in when the dryer is not running, so I dont know that it would fix the drying issue. Im guessing its some kind of pressure issue since it use to work fine but maybe now that there is more air running down the tube the dryers blower has to compete to get out? any insight would be great!