Conducted fall maintenance on Bryant Legacy 80% AFUE furnace in Mapleton. Cleaned heat exchanger cells using brush and vacuum. Replaced standard 1" filter with AprilAire 213 MERV 13 filter. Lubricated blower motor bearings. Checked and tightened all electrical connections. Cleaned condensate trap and lines. Inspected flue for proper draft using smoke pen. Performed combustion analysis with Testo 310 analyzer, adjusting air-fuel ratio for optimal efficiency. Checked thermostat calibration and replaced batteries. Left system in peak operating condition for heating season.