What is the primary function of a boiler's draft system?

The primary function of a boiler's draft system is to control the flow of air for combustion. This is crucial because combustion requires an adequate and efficient supply of air to ensure that the fuel burns properly. By managing the air intake, the draft system helps to optimize the combustion process, allowing the boiler to operate at peak efficiency and produce the required heat output. A well-functioning draft system also helps to expel flue gases, which is essential for maintaining a safe operating environment and reducing the risk of hazardous gas accumulation.

In this context, maintaining a stable water level, regulating fuel delivery, and managing pressure levels are important aspects of boiler operation but are not the primary function of the draft system. The water level is regulated by different controls and systems, while fuel delivery is managed by fuel supply systems incorporated in the boiler design, and pressure levels are controlled by safety valves and other pressure management systems. Thus, the focus on air flow for combustion distinguishes the draft system's role in boiler functionality.