PERFORM MAINTENANCE TUNE-UP. CHECK THERMOSTAT, AIR FILTER, HUMIDIFIER, HEAT EXCHANGER, HIGH LIMIT CONTROL, ENERGY CONSUMPTION, FAN CONTROL, AND ALL ELECTRICAL CONNECTIONS. LUBRICATE ALL NECESSARY MOVING PARTS, AND ADJUST BLOWER COMPONENTS. CLEAN AND CHECK BURNERS AND BURNER OPERATION. CHECK GAS PRESSURE AND FOR PROPER VENTING.