new construction town houses 6 units all the same problem. 3″ to toilet with a 2″ wet vent serving a basin on the same floor continuing up to second floor and picking up 1 washer reducing from there to a 1 1/2 vent through the roof when the washer drains it creates enough suction to completly empty the bowl of the toilet. We have tried increasing the vent size adding a extra vent on the washer and the basin with no change. also wondering if these new super capacity washer pump more wateror at a higher velocity than the plumbing code s have allowed for? thanks for any input
What you have to do is take DW. off the 2″ and run that 2″ through the roof, connect a 2″ pipe below toilet connection and frun it up to DW. and tee off with trap and connect 2″ into vent going through roof. E-Mail me at firstname.lastname@example.org and I will send you drawing.