Skip to content
Review Rating


What Are The Differences Between Normally Closed and Normally Open Solenoid Valve?

What Are The Differences Between Normally Closed and Normally Open Solenoid Valve?

Among the various characteristics of solenoid valves, two fundamental characteristics stand out: normally closed (NC) and normally open (NO). In this blog post, we will explore the differences between these two types of solenoid valves, going in-depth about each one and where they are utilized.

Solenoid valves are commonly used in various industrial and commercial applications. They are electromechanical devices that control the flow of fluids or gases through a system by using an electric current to activate the valve. There are two primary types of solenoid valves: normally closed and normally open.

Normally Closed

Designed to remain closed when there is no electrical current running through it. The valve's default state is to block the flow of fluid, ensuring that the passage is sealed off when the solenoid coil is not energized. When an electrical current is applied, the solenoid coil activates, lifting the valve plunger, and allowing the fluid to flow. This type of valve is commonly used in systems where safety and containment are critical. It is often selected for applications where the fluid needs to be blocked by default, only opening when the solenoid is energized.

Normally Open

On the other hand, a normally open solenoid valve defaults to an open position when the solenoid coil is not energized. In this configuration, the valve allows the fluid to flow freely when at rest. When an electrical current is applied, the solenoid coil activates, closing the valve and blocking the flow of fluid. Normally open solenoid valves are often chosen for applications where constant fluid flow is desirable, and the valve needs to close temporarily when activated.

Both types of solenoid valves are widely used in various industries, including HVAC, water treatment, chemical processing, and many others. They offer a reliable and efficient way to control the flow of fluids or gases in a system, making them a popular choice for many applications.

Where Are These Valves Used?

When it comes to selecting the right valve for controlling the flow of fluids, it's important to know the difference between normally closed (NC) and normally open (NO) solenoid valves. 

➊ Normally closed valves are best for situations where safety is a top priority and you want to stop fluid flow by default. They are commonly used in gas shutoff valves, emergency shutdown systems, and containment applications. 

➋ On the other hand, normally open valves are designed for applications that require continuous fluid flow, but with the option to shut off the flow temporarily when needed. They are often used in irrigation systems, water dispensers, and other systems where it's important to maintain a constant flow of fluid.


    Sometimes, a combination of both normally closed and normally open valves might be used in certain systems to meet specific control requirements. This approach offers a tailored solution for regulating fluid flow.



    The choice between normally closed and normally open solenoid valves plays a pivotal role in determining the efficiency and safety of various applications. Engineers and operators, armed with an understanding of these fundamental differences, can make informed decisions to ensure the seamless and precise control of liquids and gases in diverse industrial settings.

    Previous article Choosing the Wrong Pump Can Cause Poor Coffee Machine Performance
    Next article What Are Angle Seat Valves & How Do They Work?

    Leave a comment

    Comments must be approved before appearing

    * Required fields

    Attention OEM's!

    Are you interested in buying large quantities of valves, but still hesitant to commit? We have the perfect solution for you - our Try-A-Valve program! It's simple and risk-free. Just call one of our support team members and tell them you want to participate in the program. We will take care of all the details and ship out your chosen valve completely free of charge. We're so confident in the quality of our valves that you'll never want to use anything else. Don't miss out on this opportunity to experience the superior performance of our valves.
    Call us now at 1-800-936-2819 and join the Try-A-Valve program today!

    Compare products

    {"one"=>"Select 2 or 3 items to compare", "other"=>"{{ count }} of 3 items selected"}

    Select first item to compare

    Select second item to compare

    Select third item to compare