Chamberlain WHISPER DRIVE HD900D - Manual (Page 12)

12
INSTALLATION STEP 1
Determine the 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' (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 13) 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 inter secting 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.
• 8" (20 cm) above the high point for one-piece door without
track.
This height will provide travel clearance for the top edge of the
door.
NOTE: If the total number of inches exceeds the height
available in your garage, use the maximum height possible, or
refer to page 13 for ceiling installation.
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 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.
Header Wall
Vertical Centerline
of Garage Door
Level
(optional)
2x4
2x4
Structural
Supports
OPTIONAL
CEILING
MOUNT
FOR
HEADER
BRACKET
Unfinished
Ceiling
Door
Jamb
Hardware
One-piece door without track:
jamb hardware
8" (20 cm)
Highest
Point
of Travel
Door
Pivot
8" (20 cm)
One-piece door without track:
pivot hardware
Highest
Point
of Travel
Header Wall
Header Wall
Header Wall
Sectional door with curved track
Highest Point
of Travel
Door
2" (5 cm)
One-piece door with horizontal track
Door
Track Header Wall
Highest Point
of Travel
2" (5 cm)
Track