I was working on a scotsman today and ran across this in my laptop.
Did not know if you had this or not.
No i did not have that page thank you. On your page it list "possible causes" #4 "water level sensor failure" On Scotsman's site i found the voltage testing procedure for the sensor. On there it made no mention of how the eyes work.
I have had where the water pressure jumps the vinyl fill tube at the resovoir out slightly and the the water only partially enters the resovoir and partially spills into the bin or base of the machine. It will eventually give you an error code. It happens every so often. Must be occassional spikes in water pressure tha may make the tube jump out or if it is too long and hits the base of the resovoir it could back the tube out.
Just another thing for you to check