Completed Installation - Chamberlain 248730DM Assembly & Installation Manual

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 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 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 finished 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,
fiberglass 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 floor mounting of the
safety reversing sensor will require hardware not
provided.
Horizontal and vertical reinforcement
is needed for lightweight garage doors
(fiberglass, steel, aluminum, door with
glass panels, etc.) See page 13 for details.
Header Wall
Center of
Garage door
Gap between floor
and bottom of door
Safety Reversing
must not exceed 1/4"
Sensor
• Do you have an access door in addition to the garage
• Look at the garage door where it meets the floor. Any
• The opener should be installed above the center of the
• If your door is more than 7 feet (2.13 m) high, see rail

COMPLETED INSTALLATION

FINISHED CEILING
Support bracket &
fastening hardware
is required.
See page 12.
Slack in chain tension
is normal when
Rail
garage door is closed.
Torsion Spring
Wall-mounted
Door Control
Access
Door
Safety
Reversing
Sensor
3
WARNING WARNING
Without a properly working safety reversal system, persons
(particularly small children) could be SERIOUSLY INJURED or
CAUTION
KILLED by a closing garage door.
• The gap between the bottom of the garage door and the floor
MUST NOT exceed 1/4" (6 mm). Otherwise, the safety
reversal system may not work properly.
• The floor or the garage door MUST be repaired to eliminate
the gap.
door? If not, Model 7702CB Outside Quick Release is
required. See Accessories page.
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.
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.
extension kits listed on Accessories page 32.
Header
Bracket
Header
Wall
Garage
Door
CLOSED POSITION
Trolley
Trolley
Stop Bolt
Garage
Door
Chain
Spring
Straight
Emergency
Door
Release
Arm
Rope & Handle
Curved
Door
Arm
Door
Bracket