NEW Dometic 300 Leaking Ball Valve Seal


Well-known member
Well, after 12 years, I FINALLY upgraded from my old Dometic 200 series toilet to a Dometic 300 series, mainly for the improved ball valve seal that can be replaced/cleaned without disassembling the toilet. I was pretty dismayed when the install was complete to find that the 300 series ball valve seal didn't hold water just like my old 200 series. I had coated the new toilet seal and ball valve with plumbers silicone grease before install (and disassembled the toilet to seal all of the inside spaces to prevent reported trapped sewage in the 300 models). Anyways when the job was done, and the column of water was still leaking out, I remembered a post I had seen on an official Dometic website saying to pour hot tap water into the toilet and leave it for hours to make the seal soften and conform to the ball valve. I did this with a 2 quart pitcher of hot water, did it 2 times, and the 2nd time sealed it up good.