Chamberlain 8557 Manual page 10

Installation
5
Hang the garage door opener
To avoid possible SERIOUS INJURY from a falling
garage door opener, fasten it SECURELY to
structural supports of the garage. Concrete anchors
MUST be used if installing ANY brackets into
masonry.
HARDWARE
Lock Washer
5/16"
Hex Bolt 5/16"- 18x7/8"
Nut 5/16"-18
Hanging your garage door opener will vary depending on your
garage. Two representative installations are shown. Yours may
be different. Hanging brackets should be angled (Figure 1) to
provide rigid support. On finished ceilings (Figure 2), attach a
sturdy metal bracket to structural supports before installing the
opener. This bracket and fastening hardware are not provided.
Instructions below are for attaching the garage door opener
directly to structural supports.
5.1
Measure the distance from each side of the motor unit to
the structural support.
5.2
Cut both pieces of the hanging bracket to required lengths.
5.3
Drill 3/16" pilot holes in the structural supports.
5.4
Attach one end of each bracket to a support with 5/16"-
18x1-7/8" lag screws (not provided).
5.5
Fasten the opener to the hanging brackets with 5/16"-
18x7/8" hex bolts, lock washers and nuts.
5.6
Check to make sure the rail is centered over the door (or in
line with the header bracket if the bracket is not centered
above the door).
5.7
Remove the 2x4. Operate the door manually. If the door
hits the rail, raise the header bracket.
NOTE: DO NOT connect power to opener at this time.
FIGURE 1
Unfinished Ceiling
FIGURE 3
Measure
Distance
Hex Bolt 5/16"- 18x7/8", Lock Washer 5/16", Nut 5/16"-18
10
FIGURE 2
Finished Ceiling
Not Provided
(Not Provided)
Lag Screws
5/16"- 18x1-7/8"