A door closer is used to close a door automatically each time it is opened. This piece of hardware contains a hydraulic-based mechanism. Closers can be adjusted to make the door close more slowly or quickly and can also be used to hold the door fully open for a moment before beginning the closing process. They can take the place of a door stop to prevent damage to walls and can also be adjusted to make a door latch more firmly and securely. Many adjustments are easy to make, though it may take some time to learn which settings work best for your door.
Set the spring power. This setting ranges from 1 to 6 on most closers, with level 6 being the strongest possible setting. The average closer starts at level 3, and you must turn an adjustment screw or nut on the closer body to change this setting. Many installers fail to perform this step during initial installation, resulting in poor performance. If you have a large or heavy door, the spring power should be higher. On a lighter or smaller door, the spring power should be set lower. Consult your installation instructions to find the right power for your door or experiment with different settings until you find one that works.
Adjust the closing speed. Open the door completely and watch as it closes. The speed that the door moves from fully open to just before it latches is known as "closing" or "main" speed. It is adjusted using a small valve marked with a "C" or "S." Turn this valve clockwise to make the door close more slowly or counterclockwise to increase closing speed.
Set the latch speed. The speed during the last 10 to 15 degrees before closing is the latch speed and is adjusted using a valve that is marked with an "L." Use an Allen wrench to turn this valve clockwise to slow latching or counterclockwise to speed it up. Total closing and latching time should range from three to seven seconds.
Determine the desired level of back check. Back check is used to reduce the distance that the door can swing open, which can keep the door from damaging walls or furnishings. Turn the back check valve counterclockwise if you want the door to open further or turn it clockwise to limit how far the door can open.
Decide if the delayed closing feature is needed. This feature holds the door open for a moment before it starts the closing process. It can be useful for elderly occupants or children--anyone who may need more time to enter and to exit. The delay valve is adjusted using an Allen wrench or screwdriver. Turn the valve clockwise to increase delay time or counterclockwise to decrease delay.
Not all closers have all these adjustments. Spring power, closing and latch speed are fairly common. Back check and delayed opening are often optional features.