I have a Gerber elongated back outlet toilet with a Flushmate III in the tank. When I first installed it I used a wax seal. It blew in about 6 months. The second time I used an extended wax seal. It too blew in about six months. Any ideas for the third time?? I am planning on using a neoprene seal since it seems like the pressure from the flushmate keeps blowing wax seals. My only worry is being able to tighten the bowl enough to compress the seal without cracking the china. I’ve also noticed the saddle at the back of the bowl is not absolutely square with the bowl, so when I mount the bowl against the wall there is about 1/8″ space at the top of the saddle. Is this by design or is it a defect? Will I get a good enough seal when using the neoprene seal?? Thanks!!
Conventional wax rings are not designed for back outlet bowls. You need the wax ring with a felt insert labeled for wall hung bowls. Neoprene is better for the short term, if you can tighten it enough. Neoprene will harden and crack after a while and need replacement.