In a boiler context, what does "ventilation" refer to?

In the context of a boiler, "ventilation" specifically refers to the process of providing fresh air for combustion. Proper ventilation is essential to ensure that the boiler operates efficiently and safely. Adequate supply of oxygen is necessary for the combustion of fuel, which generates the heat needed to produce steam or hot water. Without sufficient fresh air, combustion can be incomplete, leading to the release of harmful gases, reduced efficiency, and potential safety hazards.

The other choices do not accurately reflect the concept of ventilation within a boiler system. Removing excess water pertains to water management rather than air supply, while increasing water temperature efficiently relates to combustion efficiency rather than ventilation directly. Adding chemicals to the water is a maintenance activity aimed at treating the water to prevent corrosion or scaling, which also does not involve the ventilation process.