Chamberlain 1145-1/3HP - Manual (Page 18)

INSTALLATION STEP 9
Connect Door Arm to Trolley
Follow instructions which apply to your door
type as illustrated.
SECTIONAL DOORS INSTALLATION
Make sure garage door is closed tight. Pull the manual release handle to disconnect the trolley. Manually
move outer trolley back to the center of inner trolley as shown in Figures A, B and C.
FIG A: Fasten straight door arm section to outer trolley
with a clevis pin. Secure the connection with a ring
fastener. FIG B: Bring arm sections together. Find two pairs of
holes that line up and join sections. Select holes as far
apart as possible to increase door arm rigidity.
Fasten curved section to the door bracket in the same
way.
FIG C: If holes in curved arm are ABOVE holes in
straight arm, disconnect straight arm. Cut about 6"
from the solid end. Reconnect to trolley with CUT END
DOWN as shown.
Bring arm sections together. Find two pairs of holes
that line up and join with screws, lock washers and
nuts.
Proceed to Step 1, page 20. Trolley will re-engage automatically when opener is operated.
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