Performed 1 system cooling diagnostics on the mainfloor AC system. I found the unit tripped on high pressure lockout. Customer advised me that he had just bought the home and sellers hvac system had added 3 pounds of refrigerant and replaced the contactor and capacitor on the outside unit. I reset the system and ran it in AC mode. I found that the condenser fan motor is randomly overheating and causing the system to trip on high pressure lockout. I also found that the furnace is a 70% and is over 30 years old; furnace is not safe to operate and is a potential fire and carbon monoxide hazard. The AC system is 20 years old and in poor condition. The homeowner has setup a time with an install supervisor to get an estimate to replace the mainfloor hvac system.