1ST C &C ON 3YR HEATING SYSTEM. CHECK MANIFOLD GAS PRESSURE AND FOR PROPER VENTING. ADJUST BLOWER COMPONENTS, AND LUBRICATE ALL NECESSARY MOVING PARTS. CLEAN AND CHECK BURNERS AND BURNER OPERATION. CHECK THERMOSTAT, AIR FILTER, HEAT EXCHANGER HIGH LIMIT CONTROL, FAN CONTROL, ENERGY CONSUMPTION. HUMIDIFIER, AND ALL ELECTRICAL CONNECTIONS.