Planning - Chamberlain LiftMaster Professional Security + 1255LMC-R Owner's Manual

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.
SECTIONAL DOOR INSTALLATION
Horizontal and vertical reinforcement
is needed for lightweight garage doors
(fiberglass, steel, aluminum,
door with glass panels, etc.).
See page 20 for details.
Safety Reversing Sensor
ONE-PIECE DOOR WITHOUT TRACK
Header
Wall
Gap between floor and bottom of
door must not exceed 1/4"
Safety
Reversing Sensor
Header Wall
Door
Center
Gap between floor and bottom of door
must not exceed 1/4"
Access
Door
Safety Reversing Sensor
FINISHED CEILING
Support bracket &
fastening hardware
is required.
Slack in chain tension
See page 13.
is normal when
garage door is closed.
Extension Spring
OR
Torsion Spring
Safety
Reversing
Sensor
ONE-PIECE DOOR WITH TRACK
Wall-
mounted
Door
Control
Safety
Reversing Sensor
4
Motor Unit
Wall-
mounted
Door
Control
Access Door
Motor Unit
Slack in chain tension is normal
when garage door is closed
Gap between floor
and bottom of door
must not exceed 1/4"
Access
Door
Safety
Reversing
Sensor