Chamberlain 248735S 3/4 HP Garage Door Opener User Manual


 
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.
Depending on your requirements, there are several
installation steps which may call for materials or hardware
not included in the carton.
Installation Step 1 – Look at the wall or ceiling above
the garage door. The header bracket must be securely
fastened to structural supports.
Installation Step 5 – Do you have a fi nished ceiling in
your garage? If so, a support bracket and additional
fastening hardware may be required.
Installation Step 10 – Depending upon garage
construction, extension brackets or wood blocks may
be needed to install sensors.
Installation Step 10 – Alternate fl oor mounting of
the safety reversing sensor will require hardware not
provided.
Do you have an access door in addition to the garage
door? If not, Model 7702CB Emergency Key Release is
required. See Accessories page.
Look at the garage door where it meets the fl oor. Any
gap between the fl oor and the bottom of the door must
not exceed 1/4" (6 mm). Otherwise, the safety reversal
system may not work properly. See Adjustment Step 3.
Floor or door should be repaired.
SECTIONAL DOOR INSTALLATIONS
Do you have a steel, aluminum, fi berglass or glass
panel door? If so, horizontal and vertical reinforce ment
is required (Installation Step 11).
The opener should be installed above the center of the
door. If there is a torsion spring or center bearing plate
in the way of the header bracket, it may be installed
within 4 feet (1.22 m) to the left or right of the door
center. See Installation Steps 1 and 11.
If your door is more than 7 feet (2.13 m) high, see rail
extension kits listed on Accessories page.
Header
Bracket
Trolley Stop
Bolt
Trolley
Chain
Emergency
Release
Rope &
Handle
Header
Wall
Header
Wall
Garage
Door
Door Bracket
Curved Door Arm
Garage
Door
Spring
Straight
Door
Arm
SECTIONAL DOOR INSTALLATION
Motor Unit
FINISHED CEILING
Support bracket &
fastening hardware
is required.
See page 15.
Slack in chain
tension is
normal when
garage door is
closed.
Horizontal and vertical reinforcement
is needed for lightweight garage
doors (fi berglass, steel, aluminum,
door with glass panels, etc.).
See page 23 for details.
Extension Spring
OR
Torsion Spring
Wall-Mounted
Door Control
Safety
Reversing Sensor
Safety Reversing Sensor
Gap between fl oor and
bottom of door must not
exceed 1/4" (6 mm).
Vertical
Centerline of
Garage Door