Chamberlain 3840 Garage Door Opener User Manual


 
4
Horizontal and vertical reinforcement
is needed for lightweight garage doors
(fiberglass, steel, aluminum, door with
glass panels, etc.). See page 19 for details.
Support bracket &
fastening hardware
is required.
See page 15.
— — — — — — — —
Header Wall
Safety
Reversing Sensor
Safety Reversing Sensor
Gap between floor and bottom
of door must not exceed 1/4" (6 mm).
FINISHED CEILING
Torsion
Spring
Access Door
Motor Unit
Wall-
mounted
Door
Control
Rail
Extension
Spring
OR
Vertical
Centerline
of Garage
Door
SECTIONAL DOOR INSTALLATION
Safety Reversing
Sensor
Support bracket
& fastening
hardware is required.
See page 19.
Safety Reversing
Sensor
Access
Door
Gap between floor
and bottom of door
must not exceed 1/4" (6 mm).
Wall-mounted
Door Control
Header Wall
Motor
Unit
Rail
FINISHED CEILING
ONE-PIECE DOOR WITHOUT TRACK
Safety
Reversing Sensor
Safety
Reversing Sensor
Access
Door
Gap between floor
and bottom of door
must not exceed 1/4" (6 mm).
Header Wall
ONE-PIECE DOOR WITH TRACK
15.
Planning
Identify the type and height of your garage door. Survey your garage area to see if any of the conditions below apply to
your installation. Additional materials may be required. You may find it helpful to refer back to this page and the
accompanying illustrations as you proceed with the installation of your opener.