The Jackson Corporation developed and patented the overhead concealed closer more than 40 years ago. Since that time, most manufacturers produce their overhead concealed closers to the same dimensions as Jackson: 11-5/8” length, 1-1/2” height, and 3-11/16” width. To ensure retrofit capability, spring caps are threaded to accommodate the two 1/4-20 x 7/8” bolts, and the tabs on the opposite end are threaded for screws to secure the hinge end of the closer within the frame. These hydraulic overhead concealed closers use two springs to control the closing of the door. Most overhead concealed closers are available in five fixed spring force sizes and as adjustable.
Overhead concealed closers use an arm assembly to transfer the energy from the spindle to the door. Different side and end load arms are normally transferred from the original closer onto the replacement closer. Centering the door within the opening is accomplished by adjusting the two opposite direction bolts at the front end of the arm assembly. A floor-mounted bottom pivot carries the weight of the door, keeps the door at height and enables the door to swing. When replacing an overhead concealed closer, it is strongly recommended to replace the floor pivot.
A variation of the overhead concealed closer, Ellison Doors are equipped with balanced hardware that meet ADA Standards. The elliptical opening and closing path is unique. This variation on the overhead concealed closer requires less intrusion in interior space or sidewalks compared to conventional doors. The overhead hydraulic check can be removed for service and replacement.
Some floor closers are designed for very large doors and can accommodate doors that weigh over 1,000 pounds. Shallow body closers are designed for lighter duty traffic with doors up to 250 pounds. For heavy doors, intermediate load bearing pivots are installed. For light doors, non load-bearing intermediate pivots are normally installed.
Floor closers can accommodate doors that are mounted either offset or center hung. An offset installation is when the pivot point is located ¾” from the heel (hinge) edge of the door and either ¾” or 1-1/2” from the face of the door. Center hung door are located within the center. Floor closers are available for interior and exterior doors. They can be ordered with selective hold open. Adjustment valves can include closing speed, latching speed and backcheck.
Unlike surface mounted door closer, floor closers can be ordered with built-in positive dead stop that prevents the door from swinging beyond the specified degree of opening. Handicapped floor closer models meet ANSI A117.1 . Note: Most floor closers require a portion of the threshold to be removed in order to make adjustments.
Always use the recommended size of closer for the door. Using an under-powered door closer will usually result in inconsistent closing and latching, and premature failure. Never use an over-powered closer or an adjustable closer at too high a power setting. Excessive closing force may cause the door to unintentionally hit people walking through the opening. In addition, this closer may cause premature wear on the door, hinges, pivots and the closer.
Three closing problems confront door closers: stack pressure, temporary door distortion and regulations requiring maximum force required to open a door closer-equipped door.
The term “stack pressure” describes the movement of air within a hermetically sealed building. Air pressure builds within the building as the air is forcibly moved through the air conditioning/heating intakes and ducts. This pressurization can sometimes be felt and seen when opening an exterior door. The stack pressure results in the door unable to close as the air is forced through the open door. If the HVAC system is off, the door will normally close and latch with no problem. However, with the air movement forced by the HVAC, the door closer cannot close thee door. Adjusting the closer will not solve the problem as the closer will close with excess force when there is no HVAC.
Temporary door distortion occurs to an exterior hollow metal door that is located on the sunny side of an unobstructed building. When the sun rises, the door is exposed and heats up. Depending on the construction of the door, it can begin to warp, distorting its shape. This can make the door unable to close and latch normally.
The result is the door will bow either towards or away from the jamb. The greatest variation is usually following the hottest time of the day with the greatest variation usually at the area of the latch. When the door is in this condition, it may not be able to be closed until it cools down. Eventually, the door will become warped to the point that it will not return to an operable shape.