1ST MAINTENANCE CHECK-UP UNDER SERVICE AGREEMENT FOR 2 HT UNITS, 6 YRS. LUBRICATE ALL NECESSARY MOVING PARTS AND ADJUST BLOWER COMPONENTS. CLEAN AND CHECK BURNERS AND BURNER OPERATION. CHECK THERMOSTAT, AIR FILTER, AIRFLOW, HEAT EXCHANGER, HIGH LIMIT CONTROL, FAN CONTROL, ENERGY CONSUMPTION, AND ALL ELECTRICAL CONNECTIONS. CHECK MANIFOLD GAS PRESSURE AND FOR PROPER VENTING. EVERYTHING IS RUNNING GOOD.