Chamberlain LiftMaster 311 El Manual Del Propietario página 13

ONE-PIECE DOOR WITHOUT TRACK
1. Close the door and mark the inside vertical
centerline of your garage door. Extend the line
onto the header wall above door, as shown.
If headroom clearance is minimal, you can install
the header bracket on the ceiling. See page 14.
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.
2. Open your door to the highest point of travel as
shown. Measure the distance from the top of the
door to the floor. Subtract the actual height of the
door. Add 8" (20 cm) to the remainder.
(See Example).
3. Close the door and draw an intersecting horizontal
line on the header wall at the determined height.
NOTE: If the total number of inches exceeds the
height available in your garage, use the maximum
height possible, or refer to page 14 for ceiling
installation.
EXAMPLE
Distance from top of door
(at highest point of travel) to floor . . . . .92" (234 cm)
Actual height of door . . . . . . . . . . . . . .-88" (224 cm)
Remainder . . . . . . . . . . . . . . . . . . . . . . . . .4" (10 cm)
Add . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+8" (20 cm)
Bracket height on header wall . . . . . . . .=12" (30 cm)
(Measure UP from top of CLOSED door.)
Proceed to Step 2, page 14.
Header Wall
Door
Jamb
Hardware
One-piece door without track:
jamb hardware
One-piece door without track:
pivot hardware
13
Unfinished
Ceiling
Structural
Supports
2x4
2x4
OPTIONAL
CEILING MOUNT
FOR
HEADER BRACKET
Vertical
Centerline
of Garage
Door
Header Wall
Highest Point
of Travel
Floor
Highest Point
of Travel
Header Wall
Door
Pivot
Floor