Performed AC cool check and 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. Condenser coil was cleaned. I found mold/mildew growing on the primary pan. Options for repair were presented to the customer. They chose to have surge protection installed for the air handler. I installed surge protection on the air handler and function tested the system. The system was running at the completion of service.