What happens when the water level drops in a probe type low water cut off?

In a probe type low water cut-off, the device functions as a safety mechanism to prevent the boiler from operating under unsafe conditions. When the water level in the boiler drops below a certain threshold, the probes that are immersed in the water detect the reduced conductivity due to the absence of water. This change triggers the low water cut-off.

What happens next is crucial for safety: the current to the fuel valve is interrupted, causing it to shut off. This action prevents the boiler from continuing to receive fuel, thereby stopping the combustion process and protecting the boiler from overheating or potential damage that could occur from operating without adequate water to absorb the heat.

The main role of this device is to ensure that there is always an adequate water level within the boiler, which is essential for safe operation. If the water level drops too low, the cut-off effectively interrupts the fuel supply to prevent any dangerous situations from arising. This aligns directly with the operational principle of the device, making the chosen response accurate and important for safe boiler operation.