Introduction: I do the following:
* Air-conditioner installing, replacing and repairing (central or non-central)
* Refrigerator repairing and installing (for commercial use or family use)
* Heat system repairing
Learning how an A/C and refrigerators work and how to install/repair them is what I learned from school.
I've been working in A/C and refrigerators--installing, replacing and repairing for many years.