Performed preventative maintenance on furnace for customer. Inspected the blower assembly, motor, capacitor, electrical components, heat exchanger, evaporator coil, and overall condition of furnace. Heat exchanger has no signs of cracks at this time. I checked thermostat operation, wiring, amps, temperatures and gas pressure. Cleaned the flame sensor properly and cleared out inducer port. Ignitor checked out and so did the gas valve. System is heating properly within manufactured specifications at this time.