CLEAN AND CHECK HT. CHECK THERMOSTAT, CHECK BURNERS AND BURNER OPERATION, CHECK HIGH LIMIT CONTROL, CHECK HUMIDIFIER, CHECK HEAT EXCHANGER, CHECK GAS PRESSURE AND FOR PROPER VENTING. ALSO, CHECK ALL ELECTRICAL CONNECTIONS, CHECK AIR FILTER, CHECK FREON LEVELS, CHECK CONDENSER COIL. ADJUST BLOWER COMPONENTS, LUBRICATE ALL NECESSARY MOVING PARTS. EVERYTHING IS RUNNING GREAT.