In a solid state level control with two probes, what does the second probe indicate?

In a solid state level control system that utilizes two probes, the second probe typically serves as a low water cut-off. This probe plays a crucial role in maintaining safe and optimal water levels within a tank or reservoir by providing a secondary measurement point. When the water level drops below the designated threshold indicated by the second probe, it signals the control system to take action, such as shutting off a pump or activating an alarm to prevent damage due to low water conditions.

The primary probe generally indicates when water has reached a sufficient level, while the second probe ensures that the system can respond to dangerously low levels. This dual probe setup is essential for enhancing the safety and reliability of the system, preventing pump dry run conditions, which can lead to equipment failure and potential hazards.

In this context, recognizing the specific role of the second probe as a low water cut-off is fundamental to understanding how solid state level controls operate to protect equipment and maintain system integrity.