Chamberlain 248735 3/4 HP Garage Door Opener User Manual


 
4
Safety Reversing Sensor
Horizontal and vertical reinforcement
is needed for lightweight garage doors
(fiberglass, steel, aluminum,
door with glass panels, etc.).
See page 23 for details.
Header Wall
Safety
Reversing
Sensor
Gap between floor and bottom of door
must not exceed 1/4" (6 mm).
Extension Spring
Torsion Spring
Access
Door
OR
Slack in chain tension
is normal when
garage door is closed.
Wall-mounted
Door
Control
Motor Unit
FINISHED CEILING
Support bracket &
fastening hardware
is required.
See page 16.
Vertical
Centerline
of Garage Door
SECTIONAL DOOR INSTALLATION
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.
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 finished 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 floor mounting of the
safety reversing sensor will require hardware not
provided.
Trolley
Header
Wall
Garage
Door
Header
Bracket
Straight
Door
Arm
Emergency
Release
Rope & Handle
Door
Bracket
Curved
Door
Arm
Garage
Door
Spring
Chain
Trolley
Stop Bolt
CLOSED POSITION
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 floor. Any
gap between the floor 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, fiberglass or glass
panel door? If so, horizontal and vertical
reinforcement 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.