Performed AC cool check. Checked the electrical, mechanical, safety, and performance of the system. I cleared the condensation drain line and flow tested the drain with two gallons of water. I also treated the drain line. The air filter was recently replaced. I cleaned the condenser coil. The air handler and blower wheel are dirty and have biological growth accumulating on them. The secondary drain pan has some rust spots where water had previously collected. I spoke with the homeowner about cleaning the system and the age of the system. The system was running at the completion of service.