Performed heat 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 ready to be replaced however they did not have a replacement filter at this time. The surge protector on the condenser unit was operational. I spoke with the homeowner about having a surge protector installed on his air handler since only half of the system was protected. He chose to have a surge protector installed on the air handler. I installed the surge protector and function tested the system. The system was running at the completion of service.