Normally Open vs Normally Closed Solenoid Valves (NO vs NC)
Choosing between a normally open (NO) and normally closed (NC) solenoid valve is not about preference; it’s about what must happen when power is lost . This single decision affects safety, energy use, and system behavior. “Normal” refers to the valve’s state when the solenoid coil is not energized (no power applied). Choose Normally Open (NO) if flow must continue during power loss, pressure buildup is a risk, or safety/cooling media must always be available; also more energy-efficient when the valve stays open most of the time. Choose Normally Closed (NC) if flow must stop immediately on power loss, the media is hazardous, flammable, or expensive, leaks/flooding are unacceptable, or the valve is mostly closed during normal operation. What is a normally open (NO) solenoid valve A normally open solenoid valve is open when de-energized and closes when energized. This means the fluid flows when power is OFF and stops only when power is applied. A normally open ...