Chamberlain 248730 Garage Door Opener User Manual


 
3
Planning
Identify the type and height of your garage door. If you
have a one-piece door, follow the assembly instructions
contained in this manual and refer to the Installation
Instructions One-Piece Door for installation procedures.
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 Page 10 – Look at the wall or ceiling above
the garage door. The header bracket must be securely
fastened to structural supports.
Installation Page 12 – Do you have a fi nished ceiling
in your garage? If so, a support bracket and additional
fastening hardware may be required.
Installation Page 13 – Do you have a steel, aluminum,
fi berglass or glass panel door? If so, horizontal and
vertical reinforce ment is required.
Installation Page 18 – Depending upon garage
construction, extension brackets or wood blocks may
be needed to install sensors.
Installation Page 18 – 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 Outside Quick 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.
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.
If your door is more than 7 feet (2.13 m) high, see rail
extension kits listed on Accessories page 33.
Without a properly working safety reversal system,
persons (particularly small children) could be
SERIOUSLY INJURED or KILLED by a closing garage
door.
• The gap between the bottom of the garage door and
the fl oor MUST NOT exceed 1/4" (6 mm). Otherwise,
the safety reversal system may NOT work properly.
• The fl oor or the garage door MUST be repaired to
eliminate the gap.
COMPLETED INSTALLATION
Header Wall
Rail
FINISHED CEILING
Horizontal and vertical reinforcement
is needed for lightweight garage doors
(fi berglass, steel, aluminum, door with
glass panels, etc.). See page 13 for details.
Support bracket &
fastening hardware
is required.
See page 12.
Slack in chain tension
is normal when
garage door is closed.
Center of
Garage Door
Wall-mounted
Door Control
Straight Door Arm
Emergency
Release
Rope &
Handle
Header
Wall
Chain
Trolley
Stop Bolt
Trolley
CLOSED POSITION
Garage
Door
Spring
Garage
Door
Door Bracket
Curved Door Arm
Header
Bracket
Gap between fl oor
and bottom of door
must not exceed
1/4" (6 mm)
Torsion Spring
Access
Door
Safety Reversing Sensor
Safety
Reversing
Sensor