What happens if water circulation stops in relation to low-water controls?

When water circulation stops in a system that includes low-water controls, the low-water cutoff activates. This safety device is designed to prevent the boiler from operating with insufficient water, which could lead to overheating and potentially catastrophic failures. The low-water cutoff monitors the water level and will automatically shut down the burner if the water level drops below a predetermined point.

This activation is crucial because it protects the boiler and the entire heating system from damage that could occur due to dry firing, where the boiler operates without enough water to absorb the heat produced. By shutting the system down when low water is detected, the low-water cutoff helps ensure safety and prevents hazardous conditions.

The other options do not accurately describe the function of low-water controls in this scenario. For example, a pressure relief does occur to prevent pressure buildup, but that is a separate function from what a low-water cutoff is designed to do. Similarly, while a control circuit might be activated, it would not specifically address the lack of water circulation concerning low-water monitoring. This reinforces the importance of the low-water cutoff as a critical safety feature in maintaining boiler operational integrity.