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