Chamberlain 3245 1/3 HP, 3255 1/2 HP, 3255-2 1/2 HP Determine the Header Bracket Location, INSTALLATION STEP, be mounted on the wall upside down if, necessary, to gain approximately 1/2" (1 cm)

INSTALLATION STEP 1

Determine the Header Bracket Location

WARNING

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.

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 9) 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 9.

Unfinished

Ceiling

Header Wall 2x4

Vertical Centerline

of Garage Door

Level (optional)

Header Wall

2" (5 cm) Track

Highest Point

of Travel

Door

Door

OPTIONAL

CEILING

MOUNT

FOR

HEADER

BRACKET

2x4

Structural

Supports

Header Wall Track

2" (5 cm)

Highest Point

of Travel

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.

• 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 9 for ceiling installation.

Sectional door with curved track One-piece door with horizontal track

		Header Wall
	Header Wall	8" (20 cm)
	8" (20 cm)
	Highest	Highest
Door		Point
	Point	of Travel
	of Travel	Door
Jamb
Hardware
		Pivot
One-piece door without track:		One-piece door without track:
jamb hardware		pivot hardware

8