What is the purpose of a waterflow switch?

• A. To detect water movement in the pipes and trigger the alarm.
• B. To shut off the water supply.
• C. To regulate flow rate.
• D. To measure water temperature.

Answer: (A)

The essential idea is that a waterflow switch is a sensor that detects movement of water in the pipes and sends a signal to trigger an alarm. When water starts moving—such as after a sprinkler head releases—the switch’s internal paddle or turbine is moved by the flow, changing an electrical circuit. That change is used to activate the fire alarm system or pump controller, letting responders know that water is actually flowing in the system.

This device isn’t meant to shut off the water supply, which is done by valves or interlocks; it doesn’t regulate the flow rate, which would require a flow regulator or control valve; and it doesn’t measure temperature, which would require a thermometer or temperature sensor.