FIRST CLEAN AND CHECK UNDER SERVICE AGREEMENT FOR HEATING UNIT. CUSTOMER HAVE 3 UNITS. CLEAN AND CHECK THERMOSTAT, AIR FILTER, HEAT EXCHANGER, HIGH LIMIT CONTROL, AIRFLOW, ENERGY CONSUMPTION, GAS PRESSURE, HUMIDIFIER, AND ALL ELECTRICAL CONNECTIONS. CLEAN AND CHECK BURNERS AND BURNER OPERATION. ADJUST BLOWER COMPONENTS, AND LUBRICATE ALL NECESSARY MOVING PARTS.