I left the shipbuilding industry (16 years pipefitting and three in production control) to support my wife's career. One of my last jobs after leaving shipbuilding was with a large hvac distributor. When the distributor would offer training classes to the local hvac businesses we would have 40 or so techs near my work area; I would hear them talking during breaks -- they seemed to be having a good time -- enjoying their work and camaraderie; it reminded me of my of my days as a mechanic at the shipyard. Well, as things turn and opportunities make themselves known, I am in my second class -- 'Electricity for Heating and Air Conditioning." I have a test tomorrow, and a big part of the chapter on "Reading Schematic Diagrams" is based on a Trane heat pump -- it's pretty overwhelming. I'm sure it is similar to what you experienced techs deal with on a day to day basis.
I decided to begin the classwork after finding the hvac-talk site, reading many of the comments of members and felt the values and required commitment to the trade lined up with my character -- I just need to do my part with the class work and get lined up with an apprenticeship.
Wish me luck...