The main thing you MUST KNOW is how the components in a circuit are supposed to perform and how they NORMALLY perform their functon.
That means you must know how to read a schematic drawing of the circut. Then you need be able to use the component manufacturers catalog to see how that particular companies component works.
If you know how the circuit should perform and how all the components function then you can eliminate all the ones that are performing as planned and just check out the ones that are not. This is eactly how an Electrician, Who BTW spent several years in training, works on electrical circuts.
I have read that an IRS agent (Internal Revenue Service) learns how to spot Counterfeit Bills by studying REAL Currency until they become so familiar with the real thing that a bogus bill stands out like the proerbial Sore Thumb.
I use a Hydraulic Trouble Shooting book for the Mechanical Maintenance Apprentices at a local company that is 50% on how to read a schematic, 25% on how components should function and 25% on Trouble Shooting circuits that have components wrongly applied. They take a basic class first and are familiar with Symbols and the Hardware they represent already.
At the end of the class I use some circits from the company that have a full write up on the circuit function, manufacturers literature on all the components and a written explanation of each step all the circuits go through from their At Rest Condition and each movement until returning to home position.
Each person gets their own copy of the book for furure reference. The main problem I find is it sure has cut my Trouble Shooting income at that company. However, at 75 that is not all bad.
I have had very few calls to trouble shoot Pneumatic circuits over the years except for circuits that used air to operate the actuators plus the same air to control the circuit. Air Logic circuits were a big thing just before the PLC came along. A lot of companies used Air Logic to control pneumatic circuits.
After saying all that, here are some Pneumatic companies that have Pneumatic training on the web that might be of interest.
