A door closer is a simple but vital piece of hardware, especially in a commercial or public building. It ensures doors shut securely behind people, maintaining fire safety, security, and climate control. But when it's not working correctly—slamming shut too quickly or closing too slowly—it can be both an annoyance and a safety hazard.

There are many reasons why a door can not close properly. A bent hinge or a sprung frame may be causing this problem, and these can be fixed by replacing the door. Air pressure can also be a problem, and it can oppose the motion of a door closer. In some cases, it may be necessary to replace the ent