The final stage is the latching speed, which controls the final inches or degrees of the closing arc. The force closing the door is controlled by the closer spring. The optimum installation is when there is just enough spring force left in the closer once the door is latched. If there is too much spring force left when the door is latched, this force is wasted and there is probably too much spring force being made available. Too little spring force will result in either the door not latching or the door not latching occasionally. For these reasons, the most critical adjustment is the latching speed valve.
Following the door closer manufacturer’s installation instructions is critical for the door closer to operate properly and consistently. Door closers have been designed to change their arm geometry as the door opens, increasing the leverage onto the door. This change offsets the spring compression, requiring less force exerted in order to fully open the door.
Before installing a door closer, considerations include fully adjustable versus sized door closers, the installation method, the choice of arms and positioning of the adjustable arm in relation to the shoe or foot.
Are there advantages of a fully adjustable door closer versus a sized door closer? Yes and no. The fully adjustable (one through six) door closer can be used on most door sizes, eliminating the need for a locksmith to stock multiple door closers. However, if the sized door closer offers the ability to increase the closing power by 50 percent, then the largest sized closer, a number six, can offer the closing force of a six and a half to better accommodate large or heavy doors.
Note: Some door closer manufacturers offer varying power adjustments for sized door closers. Some of the power adjustment options include 15, 35 and 50 percent adjustable increases.
The choice of installation also affects the closing power of a door closer. The Regular (also called Standard) or Top Jamb installation provides better leverage (requires less power) to operate a door than does a Parallel Arm or Track Arm installation. On average, use one closer size less for a Regular or Top Jamb installation than a Parallel Arm installation.
The Regular application mounts the door closer onto door face and the shoe onto the frame. The shoe arm (adjustable arm) assembly is mounted perpendicular to the door and frame. This is the only pull-side of the door application for a door closer. The regular application provides the most power-efficiency for a door closer.
The Top Jamb applications mounted the door closer onto the push side of the door locating the closer onto the face of the frame and the shoe onto the door. For this installation, there must be sufficient clearance for the body of the closer. Most door closer manufacturers offer mounting plate options to resolve clearance issues.
The Parallel Arm mounted door closer is installed onto the door and the arm is mounted onto the underside of the frame. Parallel arm mounted door closers require either a separate mounting bracket or the bracket is built into the parallel arm. The closer and the arm are almost parallel to the door face. When the door is closed, only the soffit plate usually projects beyond the frame face.
Note: The parallel arm application geometry is less efficient than a regular arm or top jamb application. For large or heavy doors, parallel arm installation may not be the best choice.
Unfortunately, the Parallel Arm installation has more aesthetic appeal as well as vandal resistance as the arms run parallel to the closer, not perpendicular. A door closer arm sticking out into a room is an invitation to problems.
A number of door closer arms have the option of an arm power or leverage adjustment for Regular or Top Jamb installations. The standard arm (or standard specialized application arms) has the option to increase closing power by up to 15 percent. This is accomplished by moving the adjustable arm towards the hinge side of the door. Closer manufacturers do this by either a two or three hole foot or shoe or using an offsetting shoe or foot.
In the standard position, the mounting hole is at the normal dimension. By rotating the foot or shoe, the adjustable arm is offset to provide up to 15 percent power increase. For a two hole shoe, moving the adjustable arm closer to the hinge side of the door can increase power up to 15 percent. With a three hole shoe, moving the arm from the center position to the hinge side of the door increase the power up to 7.5 percent. Moving the arm from the center position to the latch side of the door decrease the power 7.5 percent.