What type of damper is only to be used with a solid fuel-burning appliance?

The correct answer is a manual damper, which is specifically designed to be used with solid fuel-burning appliances such as wood stoves or coal-burning furnaces. Manual dampers are typically operated by hand and allow the user to control the airflow directly through the chimney or flue. This control is critical for solid fuel appliances because they require precise management of airflow to ensure optimal combustion and to prevent smoke from entering the living space.

In contrast, automatic dampers are often used in conjunction with gas or oil appliances, where the appliance can control the opening and closing of the damper based on combustion needs. Electric and motorized dampers also typically rely on electrical components to function automatically, making them unsuitable for solid fuel applications where the user needs to adjust settings manually based on the physical state of the fuel being burned. Thus, for safety and efficiency, a manual damper is the appropriately designated choice when dealing with solid fuel-burning appliances.