A: The Yale 3148 Closer Drop Plate Narrow Top Rail Drop Plate allows you to install a Yale 3000, 3301, 3501 series door closer in conditions when installing a door closer in a top jamb application where you have a low ceiling clearance prevents normal top jamb mounting. This plate allow the closer to be installed when the ceiling clearance is less than 1-7/8" and specifically
For use where the ceiling clearance is between 1-1/2" - 1-3/4"
Or for a Parallel Arm installation where you have a Narrow Top Rail and for use where
a narrow top rail prevents the closer from being mounted directly to
the door surface. This drop plate can be used to mount a closer on a top rail as narrow as 2-7/8" in height.
Or for a Parallel Rigid, Holder/Stop, holder/Stop Spring Arm fFor use where a narrow
top rail prevents the closer from being mounted directly to the door
surface. This drop plate can be used to mount a closer on a top rail as narrow as 2-9/16" in height.
Or for the Uni-Stop Arm for use where a narrow
top rail prevents the closer from being mounted directly to the door
surface. This drop plate can be used to mount a closer on a top rail as narrow as 2-7/16" in height.
All as seen on the 339'th through 345'th pages of the Yale catalog as seen here:
Download File
Be sure to review the closer series you are using, the arm you have specified and field conditions prior to installation.