Chamberlain 248754 - Manual (Page 27)

27
Door Arm
Closed
Door
Outer Trolley
Emergency Release Handle
Open Door
Door with
Backward Slant
(Incorrect)
Correct Angle
Inner Trolley
Inner Trolley
Outer Trolley
Figure 5
ALL ONE-PIECE DOORS
1. Assemble the Door Arm:
• Fasten the straight and curved door arm sections
together to the longest possible length (with a 2 or 3
hole overlap) (Figure 4).
• Make sure the garage door is fully closed. Connect
the straight door arm section to the door bracket with
the 5/16"x1-1/4" clevis pin.
• Secure with a ring fastener.
• Pull the emergency release handle, disconnecting
the outer trolley from the inner trolley by pulling
straight down on the emergency release handle and
sliding the outer trolley back toward the motor unit.
• Connect the curved door arm section to the trolley
using the 5/16"x1-1/4" clevis pin and ring fastener.
NOTE: Adjusting the limits on the following page:
• The trolley will automatically connect. If not, review
the trolley lockout feature on page 33.
• When setting the up limit on the following page, the
door should not have a “backward” slant when fully
open as illustrated below. A slight backward slant
will cause unnecessary bucking and/or jerking
operation as the door is being opened or closed
from the fully open position (Figure 5).
Nuts
5/16"-18
Lock
Washers
5/16"
Ring
Fastener
Straight
Arm
Bolts
5/16"-18x7/8"
Door
Bracket
Clevis Pin
5/16"x1-1/4"
Curved
Door Arm
Figure 4