Bob gets a call from the dispatcher that a drug store is having trouble with its cooling system. It seems that the system had been working well until yesterday afternoon when it began to get warm in the store. It is a 7.5-ton unit with a reciprocating compressor using R-22.
Bob arrives at the store at about 10:00 am and goes to the manager. She explains, "The system is about nine years old and has never had any major repairs, just a condenser fan motor about three years ago. We keep the filters changed on a regular basis. The outdoor unit is on the roof."