Craftsman 139.18452D Manuel D'instructions page 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 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.
• Do you have an access door in addition to the garage
door? If not, Model 18752 Emergency Key Release is
required. See Accessories page.
SECTIONAL DOOR INSTALLATION
Horizontal and vertical reinforcement
is needed for lightweight garage doors
(fiberglass, steel, aluminum, door with
glass panels, etc.). See page 23 for details.
Vertical
Centerline
of Garage
Door
Safety Reversing Sensor
Header Wall
Safety Reversing
Gap between floor Sensor
and bottom of door
must not exceed 1/4" (6 mm).
• 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.
Slack in chain tension
is normal when
garage door is closed.
Extension Spring
OR
Torsion Spring
Wall-
mounted
Access Door
Door
Control
4
FINISHED CEILING
Support bracket &
fastening hardware
is required.
See page 16.
Header
Bracket
Trolley
Trolley
Stop Bolt
Garage
Door
Spring
Straight
Door
Arm
Curved
Door
Header
Arm
Wall
Door
Garage
Bracket
Door
Motor unit
CLOSED POSITION
Chain
Emergency
Release
Rope & Handle