13 POINT MAINTENANCE TUNE-UP FOR 6 YR HT UNIT, 4 YR AC/COIL. LUBRICATE ALL NECESSARY MOVING PARTS AND ADJUST BLOWER COMPONENTS. CHECK MANIFOLD GAS PRESSURE AND FOR PROPER VENTING. CHECK THERMOSTAT, AIR FILTER, AIRFLOW, HEAT EXCHANGER, HIGH LIMIT CONTROL, FAN CONTROL, ENERGY CONSUMPTION, AND ALL ELECTRICAL CONNECTIONS. CLEAN AND CHECK BURNERS AND BURNER OPERATION. EVERYTHING IS OPERATING GOOD.