Which component in a boiler helps to prevent overheating?

• A. The pressure relief valve
• B. The low-water cut-off component
• C. The expansion tank
• D. The water level indicator

Answer: (B)

The low-water cut-off component is critical in preventing overheating in a boiler system. It is designed to monitor the water level within the boiler and ensure that there is a sufficient amount of water present. If the water level drops below a predetermined safe point, the low-water cut-off will automatically shut off the boiler's burner or fuel supply. This action prevents the boiler from operating without adequate water, which could lead to overheating and potentially cause damage to the boiler or create dangerous conditions.

In contrast, the pressure relief valve serves to release excess pressure, thus preventing an overpressure situation, but it does not directly monitor water levels. The expansion tank is designed to handle the expansion of water as it heats up, maintaining the system's balance but does not prevent overheating directly. The water level indicator simply provides a visual gauge of the water level without taking action to control the system in hazardous conditions. Hence, the low-water cut-off is vital for maintaining safe boiler operation and preventing overheating.