A door closer has more adjustment possibilities than you might expect, and getting a door to close "just right" may take several trips up and down a ladder. It's common to try to solve door closing problems by simply adjusting the spring tension, but tightening this tension can make the door hard to open and loosening it can make the door closer ineffective. Most door closers have adjustment screws for latch speed, swing speed and back check in addition to the spring tension adjustment screw. Which of these screws you need to turn depends on the problem you want to solve.
How a Door Closer Works
The main part of a door closer is its spring-loaded hydraulic tube. When the closer is properly attached to the door and the jamb, the spring exerts pressure on the open door to close it. The purpose of the hydraulic mechanism is to temper the action of the spring so the door closes gently instead of slamming.
Most door closers attach to the surface of the door and the jamb. Whether you have a model that mounts to the outside or the inside of the door, it always has a spring tension adjustment screw. If it has adjustment screws for latch speed, swing speed and back check depends on the model. These screws are usually on the main piston housing underneath a cover. You might have to unscrew the cover to remove it. The spring tension screw is at the end of the piston.
Diagnosing the Problem
Before you make any adjustments, open and close the door a few times in an attempt to isolate the problem you want to solve. Does the door close too fast? If so, you'll want to loosen the swing speed screw. Does the door slam slightly? That indicates an adjustment to the latch speed. Is the door hard to open? This problem may require adjustments to both the back check and spring tension screws.
Before you set up your ladder and start making adjustments, it's important to check the door hinges to make sure they are tight. Loose hinges can make the door shake, and they affect how well it closes. You should also look for other problems, such as warping or problems with the lockset, that could affect the door operation.
In general, turning an adjustment screw clockwise increases the function of the screw controls, and turning it counterclockwise decreases it. For example, turn the screw clockwise to increase spring tension, latch and swing speed. Turning the back check screw clockwise decreases the amount you can open the door without encountering resistance. The purpose of this adjustment is to prevent the door from slamming into the wall.
Some pointers can help make the adjustment process easier. Use moderation when turning one of the screws because a little goes a long way. Unless you know you have to make a big change, it's best to make adjustments in 1/8-inch increments. Adjust the spring tension first once you have the door swinging more or less how you want it, and fine-tune using the other three screws. You should also aim for a swing and latch speed that close and latch the door in about eight seconds.