I have a Tiffin 2018 Allegro Bus 40 AP with a Dometic Concerta 4100 series toilet. The bowl no longer holds water; was in Red Bay, AL and had the seal replaced, then re-adjusted number of times. Sti...
I could not find that exact model online, but I assume there is some sort of valve that slides against a rubber seal? If so then perhaps applying some plumbers grease (silicone grease) to the rubber seal will fix the problem. My toilet has a plastic ball seal that rubs against a rubber seal and will occasionally leak. I just clean off the rubber area and apply a thin coating of the silicone grease and it usually works for quite a while before needing a new application of grease.