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