How does a boiler function in a heating system?

A boiler functions in a heating system primarily by heating water or other fluids to generate steam. This steam is then utilized to provide heating throughout a building or facility. The process involves the combustion of fuel, which produces heat that is transferred to the water or fluid contained within the boiler. As the water heats up, it converts into steam, increasing in pressure and temperature. This steam can then be distributed through pipes to radiators or other heating elements, effectively transferring heat to the surrounding environment.

The other options do not accurately describe the boiler's primary function. For instance, cooling fluids would not enable steam generation, and filtering contaminants focuses on maintaining fluid quality rather than the primary heating mechanism. Additionally, circulating air is a function more associated with traditional air conditioning or forced air heating systems, not the steam generation that occurs within a boiler. Therefore, the choice that identifies the boiler's role in creating steam through the heating process is indeed the most accurate depiction of its operation.