What type of fan is used to force air into the combustion chamber of a boiler?

The choice of a forced draft fan is the appropriate answer for the type of fan used to force air into the combustion chamber of a boiler. Forced draft fans are specifically designed to push or "force" air into the combustion chamber, ensuring that there is a sufficient supply of oxygen for the combustion process. This increased air flow helps improve the efficiency of the combustion by providing a consistent and adequate amount of oxygen, which is essential for achieving optimal fuel burning and maximum heat output.

In contrast, induced draft fans are used to remove flue gases from the furnace, creating a negative pressure that helps ensure proper exhaust flow, while exhaust fans primarily focus on expelling air from a given space rather than supplying air. Recirculation fans are typically used in systems aimed at redistributing air within a space rather than directing it into a specific area like a combustion chamber. Therefore, the forced draft fan's role in supplying air directly to the combustion chamber is critical for the boiler's efficient operation.