SERVICE MAINTENANCE ON 3YR HEATING UNIT. CLEAN AND CHECK BURNERS AND BURNER OPERATION. ADJUST BLOWER COMPONENTS, AND LUBRICATE ALL NECESSARY MOVING PARTS. CHECK MANIFOLD GAS PRESSURE AND FOR PROPER VENTING. CHECK THERMOSTAT, AIR FILTER, AIRFLOW, HEAT EXCHANGER, HIGH LIMIT CONTROL, ENERGY CONSUMPTION, HUMIDIFIER, AND ALL ELECTRICAL CONNECTIONS.