Work Performed: Performed full maintenance on 2005 Lennox high-efficiency furnace. System is older but still in decent working condition. Venting shows signs of age but remains functional and clear. No immediate safety concerns found. Results: - Cleaned burners, flame sensor, and blower compartment. - Inspected and tested pressure switch, heat exchanger, inducer motor, and igniter. - Verified gas pressure, flame signal, and temperature rise within manufacturer specifications. - Checked filter and advised replacement if needed. - Inspected venting system — aging but secure and unobstructed. - Performed combustion analysis to ensure safe and efficient operation. - Furnace operating normally at time of service.