Unfortunately there aren't a lot of guys that are comfortable with schematics and control diagrams so when we get a guy from the Hall who's good at controls, we keep him.
I love that stuff. Back when I was in technical school, which was half of the day of high school, the refrigeration department had gotten in a new piece of old equipment for the guys to learn servicing on.
The schematic was missing from the equipment, so their instructorr sent a student to our department (commercial electricity) for someone to draw a diagram just from looking at the equipment itself.
To be honest (and ever-so humble), nobody was surprised when our instructor (named Bill Sparks, believe it or not) turned and pointed straight at me. I did as much teaching in that class as I did learning.
Sorry, I didn't mean to wax nostalgic and interrupt the thread.