2ND CLEAN AND CHECK UNDER SA FOR 17RY HEATING UNIT. CLEAN AND CHECK BURNERS AND BURNER OPERATION. LUBRICATE ALL NECESSARY MOVING PARTS, AND ADJUST BLOWER COMPONENTS. CHECK THERMOSTAT, AIR FILTER, AIRFLOW, HUMIDIFIER, FAN CONTROL. ENERGY CONSUMPTION, HEAT EXCHANGER, HIGH LIMIT CONTROL, AND ALL ELECTRICAL CONNECTIONS. CHECK MANIFOLD GAS PRESSURE AND FOR PROPER VENTING.