Which of these components is critical for emergency boiler shutoff?

The automatic shut-off valve is critical for emergency boiler shutoff because it is specifically designed to quickly stop the flow of fuel or steam in response to an emergency situation. This component directly impacts the safe operation of the boiler by preventing potential hazards such as overpressure, overheating, or fire hazards that can arise if the boiler continues to operate under unsafe conditions. In the event of an emergency, immediate action is often required to stabilize the system, and the automatic shut-off valve plays an essential role in achieving that by isolating the boiler from its energy source.

In contrast, while the pressure gauge, water feeder, and draft fan are important for the normal operation and monitoring of the boiler, they do not serve the same immediate and critical function during emergencies. The pressure gauge provides information about the current pressure levels but does not take action. The water feeder maintains appropriate water levels in the boiler, but it does not address emergency situations. The draft fan aids in combustion by managing airflow but is not involved in shutting down the system.