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