Performed preventative maintenance on furnace for customer. Replaced filters inside home, and reminded customer to change them in between services. I inspected the blower assembly, blower motor, electrical components, heat exchanger, burners, flame sensor, ignitor, gas valve, inducer motor and overall condition of equipment. Checked welds done for past refrigerant leak he had, and verify there aren’t any others. Cleaned flame sensor and brushed dust off the burners and components. Checked thermostat operation, capacitor, amps, temperature rise and gas pressure of furnace. Adjusted gas pressure to recommended setting and tested safety and pressure switches. As of right now, there are no issues with how the system is performing for customer. System is heating properly within manufactured specifications at this time. Recommended duct cleaning to customer to help eliminate built up dust in return duct work and supplies.