--- title: The Condenser - Actuator Closure Types description: What does “spring closed” mean? In this Condenser, we will explore the various closure types for air control and life safety dampers. Learn more here. image: https://newsstand.mcdlg-hvac.com/hubfs/MCDLG%20Blog%202025%20-%20Condenser%20-%20Actuator%20Closure%20Types%20-%20Banner%20Image.webp --- [![MCDLG Logo (Resize)](https://newsstand.mcdlg-hvac.com/hs-fs/hubfs/Logos/MCDLG%20Logo%20(Resize).webp?width=91&height=70&name=MCDLG%20Logo%20(Resize).webp)](https://mcdlg-hvac.com/) - [home](https://mcdlg-hvac.com/) - [about](https://mcdlg-hvac.com/about/) - [newsstand](https://newsstand.mcdlg-hvac.com/) - [contact](https://info.mcdlg-hvac.com/contact) - [careers](https://mcdlg-hvac.com/career-redirect/) # The Condenser - Actuator Closure Types November 10, 2025 ![The Condenser - Actuator Closure Types](https://newsstand.mcdlg-hvac.com/hubfs/MCDLG%20Blog%202025%20-%20Condenser%20-%20Actuator%20Closure%20Types%20-%20Banner%20Image.webp) What does “spring closed” mean? In this Condenser, we will explore the various closure types for air control and life safety dampers. Learn more on the Newsstand. The phrase “power open, spring closed” seems self-explanatory. This refers to the actuator’s method of opening and closing the damper. As the phrase implies, the damper will open and hold when the actuator has power.  ![A control damper set to open with power and spring closed](https://newsstand.mcdlg-hvac.com/hs-fs/hubfs/Images/Blogs/Condenser%20Articles/MCDLG%20Blog%202025%20-%20Condenser%20-%20Actuator%20Closure%20Types%20-%20Power%20Open%20Spring%20Closed.png?width=922&height=501&name=MCDLG%20Blog%202025%20-%20Condenser%20-%20Actuator%20Closure%20Types%20-%20Power%20Open%20Spring%20Closed.png) The blades will stay in full-open position until the actuator loses power. The actuator will be part of a circuit that removes power when necessary. Actuator manufacturers will explain the specifics in their installation instructions.  For most actuators, the “spring” refers to an internal spring inside the actuator. This spring drives the rotating arm back to the closed position. For life safety dampers, the return spring is often an external component tied directly to the blade. When the actuator loses power, the spring will drive the damper’s blades to the fully closed position. ![A control damper set to power open](https://newsstand.mcdlg-hvac.com/hs-fs/hubfs/Images/Blogs/Condenser%20Articles/MCDLG%20Blog%202025%20-%20Condenser%20-%20Actuator%20Closure%20Types%20-%20Power%20Open%20in%20Office.png?width=791&height=501&name=MCDLG%20Blog%202025%20-%20Condenser%20-%20Actuator%20Closure%20Types%20-%20Power%20Open%20in%20Office.png) You can also choose to configure electric actuators for “spring open, power closed” action, where the actuator holds the damper closed until it loses power. In this scenario, the damper is set to open when the building loses power. This configuration is good for smoke control dampers. Any smoke in the duct can flow through the damper to a containment zone or exhaust point. “Power open, spring closed” is the default closure type. For control dampers, the actuator will only need power to open the damper and keep it opened. Control dampers remain closed until their specific HVAC zone needs airflow. This closure type also assumes that system fans will stop during a power outage. “Spring open” is better suited for HVAC systems with built-in smoke control, where system fans can help direct smoke to unoccupied parts of the building. ![A control damper set to spring open when smoke is detected](https://newsstand.mcdlg-hvac.com/hs-fs/hubfs/Images/Blogs/Condenser%20Articles/MCDLG%20Blog%202025%20-%20Condenser%20-%20Actuator%20Closure%20Types%20-%20Spring%20Open%20in%20Smoke.png?width=653&height=450&name=MCDLG%20Blog%202025%20-%20Condenser%20-%20Actuator%20Closure%20Types%20-%20Spring%20Open%20in%20Smoke.png) Your actuators will be “power open, spring closed” by default, unless you know you need a damper that opens during power loss. The closure type will depend on the application. Are you using the actuator on a smoke damper or a control damper? What does your project need? Always review your project’s requirements before selecting dampers and actuators. For more on actuators and dampers: - [Actuators](https://newsstand.mcdlg-hvac.com/actuators-making-adjustments) - Making Adjustments - [Duct Dampers](https://newsstand.mcdlg-hvac.com/duct-dampers-for-ductwork) - Choosing, Sizing, and Installing for Duct Work - [Options for Control Dampers](https://newsstand.mcdlg-hvac.com/options-for-control-dampers) - Damper Actuators, Linkage, and More [![Click here to contact MCDLG](https://no-cache.hubspot.com/cta/default/3289606/interactive-129444095369.png)](https://newsstand.mcdlg-hvac.com/hs/cta/wi/redirect?encryptedPayload=AVxigLLcP%2BdAN2CTLWpBxvD3n8RdxXKWw0kH3ldN5EGL6QbDx5H%2FganNq5JNYuD0wLcfvaS78Z82gRzZqLL1OwxGCyGFkS1ttmay%2BEQBc1Q3BOaLYbFxNYQOsyx%2BAFbi84Rs%2B2kuJKSgo0329DyocuvMPxYA5wfyGXvFW3MOnPWy%2BfE2M1OBEeiz&webInteractiveContentId=129444095369&portalId=3289606) #### [*Previous* Life Safety in HVAC - Ceiling Radiation Dampers](https://newsstand.mcdlg-hvac.com/ceiling-radiation-dampers) #### [*next* Three Steps to Efficient HVAC Design](https://newsstand.mcdlg-hvac.com/three-steps-efficient-hvac-design) [![Mestek Commercial Damper and Louver Group](https://newsstand.mcdlg-hvac.com/hs-fs/hubfs/Logos/MCDLG_Full_08302017.png?width=350&name=MCDLG_Full_08302017.png)](https://mcdlg-hvac.com/) ##### MCDLG is a collective of top-tier HVAC brands. - Arrow United Industries - Air Balance - Cesco Products - Louvers & Dampers - Airline Louvers [![Click here to contact MCDLG](https://no-cache.hubspot.com/cta/default/3289606/d92e77ed-9f51-4dab-a150-c0a00ad89871.png)](https://cta-redirect.hubspot.com/cta/redirect/3289606/d92e77ed-9f51-4dab-a150-c0a00ad89871)  We build every louver and damper from the ground up to meet your specifications. 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