Answer:
Go to www.sloanvalve.com On the left side you'll find a box titled quick select.
Select your flushometer model and the repair guide will come up in a pdf. Troubleshooting on page 6.
Basicly you remove the top retaining ring with a strap wrench to access flush module.
Linky:http://www.sloanvalve.com/maintenancedocs/0816193.pdf
EZ ...Good Luck, Bob
Sloan's website no longer offers decent support. It really depends on the model and type used, but if your referring to a top mount unit you:
A) Remove retaining ring with (ideally) a strap wrench. More frequently a large pair of channel locks will be necessary. It will turn lefty loosey.
B) Remove cap and access flush module.
Depending on how the toilet or urinal is malfunctioning you should try replacing parts in the order of cheapest fix.
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1) Replace batteries (if not hard wired)
2) Adjust range of infra-red eye
3) Replace flush diaphragm
4) Replace operating solenoid
5) Replace flush module
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C) Remove flush module from seat (depending on cap type may still be attached)
D) Disconnect module to solenoid wire harness.
E) Unscrew and remove both solenoid and cap end with o-rings (new solenoid will come with new cap, but sometimes they stick inside the housing.
F) Separate diaphragm from housing.
G) Re-assemble in reverse.