Chamberlain WHISPER DRIVE HD900D - 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).
• 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 4
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