What does the clock icon indicate on the sentinel?

The clock icon on the sentinel indicates that a leak test is currently running. This is an important feature because leak tests are crucial in ensuring the integrity of the equipment used in mine rescue operations. During these tests, the monitoring system checks for any potential leaks in the apparatus, which is vital for maintaining a safe environment for rescuers. When the clock icon appears, it signifies that the system is actively performing this critical precaution, ensuring that the equipment remains reliable for use in emergency situations.

The other options refer to different notifications that are not associated with the clock icon. For instance, the indicator for the system being powered on would typically show a power symbol, and low battery life would be indicated by a battery icon, while maintenance requirements often use an exclamation point or wrench symbol to alert users. Therefore, recognizing the specific meaning attached to the clock icon is essential for understanding operational statuses during rescue missions.