Performed AC diagnostic on 13-year-old Goodman condensing unit. Upon my diagnostic I found that the systems R22 Refrigerant levels were very low this was the reason why the mid floor and top floor was not becoming cold. I was informed that the system was also charged up once in the past. There is a leak somewhere within the refrigeration cycle. After finding out that there was a leak present within the system I then found out that the compressor was failing under a load which was causing compressor not to energize once the condenser is turned on. System is only one stage and should be typically a multi stage or two stage system to improve efficiency and capacity to cool a three-story home. Repairs were available to charge of system with the required amount of pounds of refrigerant along with injecting a leak dye into the refrigeration cycle to return within 30 days to investigate possible leak location. Replacement options were discussed with Mr./Mrs. Olympia over the phone