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