Performed clean and check on gas furnace and humidifier. Conducted combustion analysis, measured temperature rise, tested all electrical components, inspected gas supply, burner, inducer and blower assemblies. Cleaned flame sensor, changed humidifier pad and filter. Changed t-stat batteries that customer provided. Tested t-stat operations. Checked drains and cycled system in heat. Inducer motor has a vibration at mounting bracket but is otherwise operating normally. Found everything else to be operating correctly at this time. Discussed findings with customer and collected payment for past due 2018 cm.