Performed preventative maintenance on furnace. Customer changed filters in home recently. I inspected the ductwork, blower assembly, motor, capacitor, electrical components, heat exchanger, evaporator coil and overall condition of equipment in attic. Cleaned flame sensor and burner compartment. Checked thermostat operation, wiring, amps, temperatures and gas pressure of furnace. Furnace is heating properly within manufactured specifications at this time. No issues were found with system operation.