EXCERPT: For adjustment and repair of Door Closers, often used in offices and commercial buildings. Also known as: Mechanical door closer, office door closer, automatic door closer.
For information on pneumatic storm door closers, see this article: Storm Door Closer Maintenance, Repair and Adjustment
Disclaimer. This information may be inaccurate, incomplete, or dangerous. You are responsible for your actions. I caution you to NOT disassemble the main cylinder, your closer may have a strong spring inside that can cause serious injury if an end cap is removed.
This article is an updated version of the original page .
- Hydraulic Door Closers close a door automatically at an adjustable speed.
- A Door Closer is usually mounted at the top of a door or
above it on the jamb. There are also internal models that are installed hidden inside the door frame for a cleaner look.
- An internal Spring applies force to the Arm to close the door. Hydraulic fluid (oil) flows through pathways inside the closer. The resistance/restriction to fluid flow determines the door closing speed.
- Spring strength and adjustment (if any) varies by model. Heavier doors require stronger door closers.
- Door closers are matched to their application, based on door size and weight, and the corresponding strength needed to close them properly.
- Adjustable Spring tension allows models so equipped to work well for doors of sizes within their range of adjustment.
The operation of a door is controlled by the Door Closer in 3 basic zones: