What is the standard operating voltage supplied to irrigation controllers?

What is the standard operating voltage supplied to irrigation controllers?

• A. 24 VAC (low voltage)
• B. 120 VAC
• C. 240 VAC
• D. 12 VAC

Answer: (A)

The key idea is that irrigation controllers use low-voltage power to run their solenoid valves. The standard operating voltage is 24 volts alternating current (VAC). This low voltage is produced by a small transformer, making the control circuits safer and simpler to wire, while still delivering enough current to energize the valve solenoids through the controller’s relays. Using 24 VAC has practical advantages: it's widely supported by irrigation components (solenoid valves, wiring, and controllers), easy to step down from household power, and reduces shock risk compared to higher line voltages. By contrast, line voltages like 120 VAC or 240 VAC are not typical for the valve control circuits in standard irrigation systems, and 12 VAC is not the standard for these controllers.

The key idea is that irrigation controllers use low-voltage power to run their solenoid valves. The standard operating voltage is 24 volts alternating current (VAC). This low voltage is produced by a small transformer, making the control circuits safer and simpler to wire, while still delivering enough current to energize the valve solenoids through the controller’s relays.

Using 24 VAC has practical advantages: it's widely supported by irrigation components (solenoid valves, wiring, and controllers), easy to step down from household power, and reduces shock risk compared to higher line voltages. By contrast, line voltages like 120 VAC or 240 VAC are not typical for the valve control circuits in standard irrigation systems, and 12 VAC is not the standard for these controllers.