What is true about the signals from water level supervisory devices?

Water level supervisory devices are designed to monitor and communicate specific conditions regarding the presence of water in a system, particularly in contexts such as fire protection systems. The correct statement indicates that these devices provide two distinct signals for low and normal water levels. This dual reporting capability is crucial for maintaining system integrity and ensuring that adequate water levels are maintained for fire suppression systems.

When the water level drops below a predetermined threshold, the device will signal a low water condition, alerting operators or monitoring systems of a potential problem that might affect the performance of firefighting equipment. Conversely, when the water level returns to the normal range, the device provides a corresponding signal to confirm adequate water supply, which is essential for troubleshooting and operational readiness.

This feature of utilizing two signals enhances situational awareness for maintenance personnel and helps prevent false alarms, ensuring that actions are taken only when necessary. It also distinguishes this system from others that may report solely on low or high water levels, thus providing a more comprehensive understanding of the water system's status.