What does a low-water cut-off device do?

A low-water cut-off device is a crucial safety feature in boiler systems that is designed to prevent potential hazards associated with low water levels. Specifically, its primary function is to shut off the burner if the water level drops below a certain threshold. This is critical because insufficient water levels can lead to overheating, tube failures, and even catastrophic damage to the boiler.

When the water in the boiler falls below the predetermined level, the low-water cut-off activates, sending a signal to halt the combustion process, thereby preventing the heat source from creating steam without adequate water. This safety mechanism ensures that the boiler operates within safe parameters, preserving both the integrity of the boiler and the safety of its operators.

In contrast, the other options pertain to functions that are not the primary role of a low-water cut-off device. For example, increasing the water supply automatically and regulating fuel input based on water levels do not describe the cut-off device's function, and controlling steam pressure is typically managed by different components within the boiler system. Therefore, understanding the role of the low-water cut-off is essential for boiler operation safety and maintenance.