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