Chamberlain 3850 - Manual (Page 22)

22
Door Arm
Door Arm
Connector Hole
Closed
Door
Outer Trolley
Emergency Release Handle
Inner Trolley
Outer Trolley
Open Door
Door Arm Correct Angle
Door with
Backward Slant (Incorrect)
Inner 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 27.
• 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.
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