He was very professional, He explained to us about...

He was very professional, He explained to us about the problems he found with the a/c unit inside and outside , wish were minor, and how to keep them to become big problem.
He didn't only talked about them, but also took the time show us, and told us what these little problems can do to the a/c unit inside, and outside, He told us when, and how to do it our self, and when WE MUST CALL FOR PROFESSIONAL HELP.