The fire alarm control unit shows a supervisory signal on the display.

Asupervisory signalindicates a condition thatrequires attention but is not an alarm. In sprinkler systems, one of the most common supervisory signals comes from avalve tamper switch, indicating a partially closed valve, or sometimes awaterflow switch resetissue.

NFPA 72 (2022), Section 3.3.269:

"Supervisory Signal — A signal indicating the need for action in connection with the supervision of guard tours, the fire suppression systems, or equipment or maintenance features of related systems."

Also:Table A.10.14.2.1

Shows thatwaterflow valves and tamper switchesare typical sources of supervisory signals.

So the correct answer — awaterflow alarmimplies something abnormal with the fire protection system, possibly indicating a tamper switch or system supervisory issue.

Correct answer: D. A waterflow alarm has been activated

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