MAINTENANCE TUNE-UP FOR 6YR HEATING UNIT. CLEAN AND CHECK BURNERS AND BURNER OPERATION. CHECK HEAT EXCHANGER, HIGH LIMIT CONTROL, FAN CONTROL AIRFLOW, HUMIDIFIER, ENERGY CONSUMPTION, THERMOSTAT, AIR FILTER, GAS PRESSURE , AND ALL ELECTRICAL CONNECTIONS. LUBRICATE ALL NECESSARY MOVING PARTS, AND ADJUST BLOWER COMONENTS.