I told him straight away that I was honored to work for him, and I would do whatever I could to learn the HVAC business his way
Some things are learned from books, and some things need to be learned through experience. However when you learn a trade, you need to do both. You have to learn by doing, but also study and read and learn as much as you can. No matter what trade you want to follow, there is nothing more beneficial to the process than finding a mentor. A mentor can guide you through the practicality of the job, leading by example and giving you the experience you need to succeed. In the world of HVAC, the tech is constantly evolving, so the workers need to evolve just as quickly. My mentor was an old, gruff man who called himself Ox, and was the sole proprietor of an HVAC repair shop. Ox didn’t do a lot of house calls anymore, and was looking to pass on his HVAC wisdom and possibly his business to someone younger. I told him straight away that I was honored to work for him, and I would do whatever I could to learn the HVAC business his way. Ox was a man of few words, and gave me three pieces of advice for learning the HVAC trade – be on time, pay attention, and don’t ask to go home. I followed those three rules religiously, and over the course of months learned more and more about heating and cooling systems. After a while he gave me an advance on my pay to sign up for the HVAC certification program, which at that point would be a cake walk for me!  
steam boiler