Chamberlain Whisper Drive Security+ 459950 Owner's Manual page 27

ALL ONE-PIECE DOORS
1. Assemble the Door Arm
IMPORTANT: The groove on the straight door arm MUST
face away from the curved door arm (Figure 5).
• Fasten the straight and curved door arm sections
together to the longest possible length (with a 2 or 3
hole overlap) (Figure 5).
• 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 34.
• 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 6).
Figure 6
Inner Trolley
Door Arm
Closed
Door
Outer Trolley
Inner Trolley
Open Door
Figure 5
CORRECT
Straight
Door
Arm
(Groove
facing out)
Door
Bracket
Clevis Pin
5/16"x1-1/4"
Emergency
Release Handle
Correct Angle
27
Straight
Door
Arm
Curved
Door
Arm
Ring
Lock
Fastener
Washers
5/16"
Straight
Arm
Bolts
5/16"-18x7/8"
Outer Trolley
Door with
Backward Slant
(Incorrect)
INCORRECT
Curved
Door
Arm
Nuts
5/16"-18
Curved
Door Arm