What indicates that a device requires monitoring when it comes to fire safety systems?

A supervisory signal other than pump running is essential for fire safety systems because it provides critical information about the status of various components within the system. Supervisory signals can indicate issues such as loss of power, communication failures, or malfunctions that may not trigger an alarm but still require attention to maintain system integrity and ensure the safety of the environment.

Monitoring these supervisory signals is crucial, as they can alert personnel to potential problems before they escalate into emergencies. If these signals go unmonitored, it could lead to undetected faults, posing a significant risk to life and property in the event of a fire situation.

The other choices, while they do indicate issues, do not specifically denote the need for monitoring the system. A signal indicating the system is off or a low battery warning refers to operational states, and a notification to check the equipment suggests an action rather than a specific supervisory indication that points to ongoing monitoring needs. Therefore, a supervisory signal that is otherwise not related to active alarms or system operations is key to ensuring comprehensive oversight of fire safety systems.