2ND MAINTENANCE CHECK-UP UNDER SERVICE AGREEMENT FOR 4YR HEATING SYSTEM. RENEWED SERVICE AGREEMENT. CHECK HEAT EXCHANGER AND HIGH LIMIT CONTROL. CLEAN AND CHECK BURNERS AND BURNER OPERATION. CHECK MANIFOLD GAS PRESSURE AND FOR PROPER VENTING. LUBRICATE ALL NECESSARY MOVING PARTS AND ADJUST BLOWER COMPONENTS. CHECK THERMOSTAT, AIR FILTER, AIRFLOW, ENERGY CONSUMPTION. FAN CONTROL, HUMIDIFIER, AND ALL ELECTRICAL CONNECTIONS.