Came out to perform preventative maintenance on furnace. Discussed with customer about maintenance being performed, filters, and any issues. Customer supplied filters for me to change out and stated that everything seems to be working fine. I changed out the filters in home. 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.