To what extent can I work on my own central HVAC system?

Instead of keeping regular hobbies like normal people do—be it painting, cooking, or practicing an instrument—I spend my free time learning to fix everything around the house myself.  I have learned basic wiring techniques for installing new lighting fixtures and even repaired several p-traps in my two bathrooms. I even took up soldering last month in hopes of repairing one of my computer monitors at some point in the near future.  But when it comes to my heating and cooling system, with all of the expensive parts and components working in tandem, I am afraid of touching anything myself. Obviously I change my air filter alone but I was curious if it was safe for me to flush my condensate drip line without supervision from an HVAC technician.  So when I was getting routine maintenance this week, I asked my technician to show me whatever type of maintenance I can do myself with my heating and cooling system. Not only did he show me how to correctly flush my drip line, but he also taught me how to take apart the lid on my condenser unit outside and spray it clean with water to dislodge pine needles and yard debris from the fan blades.  When I asked him if I could clean my evaporator coil myself, he advised against it. The part is extremely fragile and prone to damage if you use the wrong cleaning solution and corrode the delicate metal fins that make up the component. My technician uses this spray cleaner that is designed specifically for cleaning dehumidifier and air conditioner evaporator coils. He showed me how he goes about sanitizing these components for mold and mildew and offered to clean the coil on my portable dehumidifier in the process.  I can’t learn enough DIY to satisfy my endless curiosity.

heating and air