2ND CLEAN AND CHECK FOR 4YR HEATING SYSTEM. CHECK HEAT EXCHANGER, HIGH LIMIT CONTROL, GAS PRESSURE, THERMOSTAT, AIR FILTER, FAN CONTROL, HUMIDIFIER, ENERGY CONSUMPTION, AND ALL ELECTRICAL CONNECTIONS. CLEAN AND CHECK BURNERS AND BURNER OPERATION. LUBRICATE ALL NECESSARY MOVING PARTS, AND ADJUST BLOWER COMPONENTS. RENEWED SERVICE AGREEMENT.