Furnace tune-up and safety inspection. Tested all mechanical components. Cleaned all sensors. Changed the furnace filter that the customer provided. Hadn’t been changed in a year. Found ignitor and flame switch were very corroded. The customer agreed to replace both parts. Cleaned the exhaust pipe out. Tested gas valve voltage and inlet/outlet pressures. The system is clean, heating, and operating adequately at this time. The system is near the end of its lifetime due to the age of the equipment. Performed free plumbing inspections.