I can repair the a/c system

I own a rental property and I have been trying to learn more about HVAC.

It seems my tenants are always calling me about HVAC related things.

Last season, I had to go over to my rental property and babysit the HVAC supplier for over an hour, however; the HVAC company messed around with the heating equipment. I asked him if I could look over his shoulder. The guy was actually really nice and let me ask a bunch of questions. I actually learned about the inner laborings of HVAC equipment plus what small things can go wrong. I learned how to open it up, disinfect it, and change small parts out. Now that the hot season is around, my tenants called me about an A/C issue, but rather than get the HVAC specialist back out there, I decided to test out my modern knowledge. I started out changing the air filter and cleaning the inside. I then fixed the clogged drain, plus removed mold from the cooling coil. When none of that worked, I started looking at the damper with the A/C system. The rental component is technically zone control. The damper in the HVAC duct was not opening correctly to let in cool air. I think there was an issue with the wiring. I also observed both the indoor and outdoor component were frozen solid. I first turned on the heat to defrost the units. Then I messed with the damper. I got the A/C system back up and running in under an hour. No Heating, Ventilation, and no A/C supplier necessary for this fix!

air conditioning filter