Installation Step; Determine The Header Bracket Location - Chamberlain LiftMaster 311 El Manual Del Propietario

INSTALLATION STEP 1

Determine the Header Bracket
Location
WARNING
To prevent possible SERIOUS INJURY or DEATH:
• Header bracket MUST be RIGIDLY fastened to
CAUTION
structural support on header wall or ceiling, otherwise
garage door might not reverse when required. DO NOT
install header bracket over drywall.
• Concrete anchors MUST be used if mounting header
bracket or 2x4 into masonry.
• NEVER try to loosen, move or adjust garage door,
springs, cables, pulleys, brackets, or their hardware, all
of which are under EXTREME tension.
• ALWAYS call a trained door systems technician if
garage door binds, sticks, or is out of balance. An
unbalanced garage door might not reverse when
required.
Installation procedures vary according to garage door
types. Follow the instructions which apply to your
door.
SECTIONAL DOOR AND ONE-PIECE DOOR
WITH TRACK
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
(1.2 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 14) 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 here and on page 13.
3. Open your door to the highest point of travel as
shown. Draw an intersecting horizontal line on the
header wall 2" (5 cm) above the high point. This
height will provide travel clearance for the top edge
of the door.
Proceed to Step 2, page 14.
Header
Wall
Header Wall
2" (5 cm)
Highest Point
of Travel
Door
One-piece
door with
horizontal
track
12
Finished
Ceiling
2x4
WARNING
WARNING
Vertical
Centerline
of Garage Door
Ceiling
Track
Sectional door
with curved
track
Header Wall
2" (5 cm)
Highest Point
of Travel
Door
Structural
Supports
Track