A lady list moderator told me not to go into to much details on fixing things on here as she feels people are not able to comprehend advice (mentally to understand)
Without going into technical detail in order to give any advice one has to know if the flushometer is a piston or diaphragm type and and knowing if it is a Coyne Delany Rex, Sloan royal, Sloan Gem , Turn to silence flush boy would sure help a lot
Piston/ diaphragm / Navel ?? If you give the type of flushometer then a plumber can tell you exactly how it is put together
Flushometer or tank and bowl?
By discharging a predetermined rate of flow and GPM using either a piston assembly or diaphragm
one inch for a water closet, 3/4 for urinal
Adjust the flushometer / Fill valve / flapper
3.14159 x the opening and then get the pressure / volume from the flushometer
Handicapped ? residential? hospital type with bedpan washing capabilities?
These are bedpan cleaning systems. Yes, it looks like they are still available online.
It lifts the tank flapper /bulb connected to the Douglas Valve On a Flushometer it moves the piston assemble aside
Depends on the type of flushometer where the shut off is located or it could be a manually open and automatic closing type
A vacuum breaker tail piece 11/2" x 3/4" x 9"
Flushometer type needs at least 30 PSI to operate semi decently 50 PSI or more would be ideal