What does the low-water cut off valve do in a hydronic system?

The low-water cut-off valve plays a critical role in maintaining the safety and efficiency of a hydronic system. Its primary function is to deactivate the system when the water level drops below a certain threshold. This is essential because operating a hydronic system with insufficient water can lead to overheating, equipment damage, or even system failure. By shutting down the system in low-water conditions, the cut-off valve helps prevent these risks, ensuring the longevity of the system and the safety of the environment where it operates.

In contrast, the other options describe functions that are not performed by the low-water cut-off valve. Increasing water pressure is typically managed by pumps or pressure regulators, while enabling water supply involves the system's feed mechanisms, which are separate from the cut-off functionality. Providing overflow protection relates to ensuring that excess water does not cause spillage or flooding, which is a different aspect of system management and is secured through other devices like overflow valves.