Which safety feature should be installed on a steam or water boiler?

Installing a low water cut-off control on a steam or water boiler is essential for safety because it protects the boiler from operating without sufficient water levels. If the water level drops too low, it can cause the boiler to overheat and potentially lead to a catastrophic failure, such as a boiler explosion. The low water cut-off control automatically senses the water level and will shut off the burner or heating element if the level falls below a predetermined point, ensuring that the boiler operates safely and efficiently.

This safety feature is especially critical in preventing damage to the boiler itself and ensuring the safety of the facility and personnel. The other options, while important for overall boiler operation, do not specifically address the risk associated with low water levels in the same direct manner as the low water cut-off control.