Inspected all the electrical components. Customer replaced filter this month. Cleared all the tubing going to the inducer, pressure switches and collector box. Cleaned the burners, flame sensor and burner compartment. Tested the amp draw for the blower motor and inducer. Both are operating within the manufacturer specs. Made sure all drainage tubing was clear of debris. System had a temperature rise of 53°. Performed a combustion analysis on the furnace. System is operating at 94.6% efficiency with a CO level of 18ppm. System is operating properly at this time. Customer wanted to prepay for spring AC maintenance 2023. Customer total today was for fall maintenance 2022 and spring maintenance 2023. Customer due for renewal in fall 2023. Model #GMSS920603BNAA Serial #1408208185