CLEAN AND CHECK 7YR HEATING UNIT. CLEAN AND CHECK BURNERS AND BURNER OPERATION. CHECK THERMOSTAT, AIR FILTER, AIRFLOW, ENERGY CONSUMPTION, HEAT EXCHANGER, HIGH LIMIT CONTROL, FAN CONTROL, HUMIDIFIIER, AND ALL ELECTRICAL CONNECTIONS. CHECK MANIFOLD GAS PRESSURE AND FOR PROPER VENTING. LUBRICATE ALL NECESSARY MOVING PARTS, ADJUST BLOWER COMPONENTS.