Today I arrived on site and performed a winter tune-up on the system. Indoor Unit (Furnace - Garage): Replaced the pleated 1" filters (20x20, 12x24). Confirmed the indoor coil is in good, clean condition. Outdoor Unit (Straight Cool - Side of House): Cleaned the outdoor coil; it's now in good condition. Electrical Components: Tested and confirmed proper operation of the blower motor, inducer draft motor, furnace control board, and electrical wiring within manufacturer's specifications. System Components (Good Condition): Inspected and verified proper function of the blower wheel, burners, exhaust flue, heat exchanger, and secured electrical wires. Testing & Measurements: Carbon monoxide levels: 0.00 PPM. Return air temperature: 76.0 Degrees Fahrenheit. Supply air temperature: 121.0 Degrees Fahrenheit. Condensate Drain: Cleared the drain line and tested the safety switch. Confirmed the drain line is strapped and secured. Additional Actions: Dusted the return grills and thermost