CLEAN AND CHECK HEATING UNIT TO MAKE SURE EVERYTHING IS RUNNING PROPERLY. CHECK ALL ELECTRICAL CONNECTIONS, CHECK HEAT EXCHANGER, CHECK HIGH LIMIT CONTROL, CHECK HUMIDIFIER, THERMOSTAT, AIR FILTER, GAS PRESSURE AND FOR PROPER VENTING. CLEAN AND CHECK BURNERS AND BURNER OPERATION. LUBRICATE ALL NECESSARY MOVING PARTS AND ADJUST BLOWER COMPONENTS.