MAINTENANCE TUNE-UP FOR 8 YR HT UNIT. COMPRESSOR VALVES LOUD DUST IN A/H. GAVE S/A LIKES COMPANY. 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, AIRFLOW, AIR FILTER, HEAT EXCHANGER, HIGH LIMIT CONTROL, FAN CONTROL, ENERGY CONSUMPTION, AND ALL ELECTRICAL CONNECTIONS. EVERYTHING IS RUNNING GREAT.