Chamberlain LiftMaster Security + 3270 1/2 HP Manuel D'instructions page 4

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 fi nd it helpful to refer back to this page and the
accompanying illustrations as you proceed with the installation of your opener.
SECTIONAL DOOR INSTALLATION
Horizontal and vertical
reinforcement is needed for
lightweight garage doors
(fi berglass, steel, aluminum,
door with glass panels, etc.).
See page 19 for details.
Safety Reversing Sensor
ONE-PIECE DOOR WITHOUT TRACK
Header Wall
Safety
Reversing
Sensor
Header Wall
Vertical
Centerline
of Door
Gap between fl oor and bottom of
door must not exceed 1/4" (6 mm)
Wall-mounted
Door
Control
Safety
Reversing Sensor
Gap between
fl oor and bottom
of door must not exceed 1/4" (6 mm)
FINISHED CEILING
Support bracket &
fastening hardware
is required.
See page 11.
Extension Spring
OR
Torsion Spring
Safety
Reversing
Sensor
FINISHED CEILING
Support bracket &
fastening hardware
is required.
See page 11.
ONE-PIECE DOOR WITH TRACK
Access
Door
4
Wall-mounted
Door Control
Access
Door
Motor Unit
Gap between
fl oor and bottom
Safety
of door must not
Reversing
exceed 1/4" (6 mm)
Sensor
Motor Unit
Access
Door
Safety
Reversing
Sensor