Primarily is a Big Word when you talk Stationary Engineer, but if I had to put them in order, I would go with H.V.A.C as number 1. You will also need to know about High and Low pressure boilers, water treatment, ice machines, door hardware, emergency generators, sewage ejector pumps, domestic water systems, etc., etc. About the only thing I did not work on were the Elevators, which are usually contracted out. Do yourself a favor and join the Refrigeration Service Engineers Society "RSES", as they have a wealth of information. I'm an active member for 30 years now. Also, go pick up a few applications at the City, County, State, etc, and read the requirements. I Hope this Helps You!
Thanks so much. Just curious, were you a chief engineer at an office property,school, hotel, etc? Or did you work as a central plant operator for a steam plant etc?
As a high school student who is an aspiring building/stationary engineer I would love to hear more about your experiences.