The maximum delay (retard) on a waterflow switch is which of the following?

• A. 60 sec
• B. 90 sec
• C. 120 sec
• D. 30 sec

Answer: (B)

Waterflow switches can include a built-in retard, a deliberate delay before the alarm signal is sent after water movement is detected. This delay helps filter out brief, non-fire-water movement—like system checks, water hammer, or cosmetic valve operations—so you don’t get false alarms.

The maximum delay used for this function is ninety seconds. That length of time provides a balance: long enough to confirm that the flow is sustained, but short enough to still trigger a timely fire alarm in a real incident. Values shorter than that (like thirty or sixty seconds) can reduce nuisance alarms but aren’t the maximum. A longer delay (such as twelve minutes) would delay alarms too much and could violate guidelines meant to protect life and property.