Heat pump checklist or narratives?

I’d like to include some narratives for the inspection of heat pumps in the library, but I’ve only ever seen one and I don’t know much about them. They’re not too common in Colorado. I don’t really have the time to learn all about them, I just want to provide some narratives for common problems.
All the links I find to checklists on the boards are obsolete. Anyone got any suggestions?