What component is used to control a balanced draft in a boiler?

The component that is used to control a balanced draft in a boiler is the outlet damper. In boiler systems, especially those that employ a balanced draft system, maintaining the correct air-to-fuel ratio is critical for efficient combustion. The outlet damper is crucial because it regulates the flow of flue gases leaving the boiler. By adjusting the amount of gas that can exit, the damper helps balance the draft pressure, ensuring that both the intake of combustion air and the exhaust of combustion gases are properly managed.

This balancing is essential for optimal boiler operation, as it prevents issues such as backdraft or excessive pressure on the combustion side of the system, which could affect efficiency or lead to unsafe conditions. The outlet damper works in conjunction with other components, such as blower fans and intake valves, but it specifically plays the key role in controlling the exit flow to maintain that balance.

While the other components mentioned—blower fans, intake valves, and exhaust stacks—contribute to various aspects of combustion and airflow, they do not have the direct and specific function of controlling balanced draft in the way the outlet damper does.