Why is 'holding current' important in irrigation?

• A. System wont come on
• B. System wont stay open
• C. The timer will have to be reset
• D. System wont stay closed

Answer: (B)

Holding current is the current that keeps a solenoid valve energized so it stays open during a zone’s run. When a zone starts, the solenoid is energized to open the valve, and that energization must be maintained to keep water flowing. If holding current is lost, the valve’s spring will push it back toward the closed position, stopping flow. So the irrigation system won’t stay open once holding current drops. The other ideas don’t describe what happens to the valve during a run: initial actuation can occur, but it won’t persist without the holding current; the timer wouldn’t necessarily need a reset because of this; and the situation isn’t that the system wouldn’t stay closed—it's that it won’t stay open.