13 POINT MAINTENANCE TUNE-UP FOR 15 YR HT UNIT. LUBRICATE ALL NECESSARY MOVING PARTS AND ADJUST BLOWER COMPONENTS. CLEAN AND CHECK BURNERS AND BURNER OPERATION. CHECK MANIFOLD GAS PRESSURE AND FOR PROPER VENTING. CHECK THERMOSTAT, AIRFLOW, AIR FILTER, HEAT EXCHANGER, HIGH LIMIT CONTROL, FAN CONTROL, ENERGY CONSUMPTION, AND ALL ELECTRICAL CONNECTIONS. EVERYTHING IS RUNNING GREAT.