Chamberlain B353 Guide De L'utilisateur page 5

Installation
If you are replacing a LiftMaster
existing header bracket, see Installation step 1 in the Installation Manual.
Installation 1- Install the Header Bracket
To prevent possible SERIOUS INJURY or DEATH:
Header bracket MUST be RIGIDLY fastened to structural support on header wall or ceiling, otherwise garage door might NOT
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reverse when required. DO NOT install header bracket over drywall.
Concrete anchors MUST be used if mounting header bracket or 2x4 into masonry.
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NEVER try to loosen, move or adjust garage door, springs, cables, pulleys, brackets, or their hardware, ALL of which are under
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EXTREME tension.
ALWAYS call a trained door systems technician if garage door binds, sticks, or is out of balance. An unbalanced garage door
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might NOT reverse when required.
Determine Header Bracket Location
Installation procedures vary according to garage door types. Follow the instructions which apply to your door.
1. Close the door and mark the inside vertical centerline of the garage door.
2. Extend the line onto the header wall above the door. You can fasten the header bracket within 4 feet (1.22 m) of the left or
right of the door center only if a torsion spring or center bearing plate is in the way; or you can attach it to the ceiling (see page
6) when clearance is minimal. (It may be mounted on the wall upside down if necessary, to gain approximately 1/2" (1 cm). If
you need to install the header bracket on a 2x4 (on wall or ceiling), use lag screws (not provided) to securely fasten the 2x4 to
structural supports as shown .
3. Open your door to the highest point of travel as shown. Draw an intersecting horizontal line on the header wall above the high
point:
2" (5 cm) above the high point for sectional door and one-piece door with track.
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8" (20 cm) above the high point for one-piece door without track.
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This height will provide travel clearance for the top edge of the door. NOTE: If this height is more than the space available, use the
maximum height possible, or refer to page 6 for ceiling installation.
® ® ®
, Chamberlain , or Craftsman garage door opener you may use the
Header Wall
Vertical Centerline of Garage Door
Level
(Optional)
Sectional door with curved track
Header Wall
2" (5 cm)
Track
Highest
Point of
Travel
Door
One-piece door without track:
jamb hardware
Header Wall
8" (20 cm)
Door
Highest
Point of
Travel
Jamb
Hardware
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OPTIONAL CEILING MOUNT
FOR HEADER BRACKET
2x4
Structural
Supports
Unfinished
Ceiling
One-piece door with horizontal track
Header Wall
2" (5 cm)
Door
Highest
Point of
Travel
One-piece door without track:
pivot hardware
Header Wall
Door
2x4
Track
8" (20 cm)
Highest
Point of
Travel
Pivot