Chamberlain AccessMaster M885 - Assembly; Attach the Rail to the Garage Door Opener; Tighten the Chain

3
Assembly
1 Attach the Rail to the Garage Door Opener
To avoid possible SERIOUS INJURY to finger from moving garage door opener:
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ALWAYS keep hand clear ofsprocket while operating opener.
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Securelyattach sprocket cover BEFORE operating.
To avoid SERIOUS damage to garage door opener,use ONLY those bolts/fasteners mounted in the
top of the opener.
NOTE: ONLY use the bolts removed from the garage door opener. Place the garage door opener on
the packing material to prevent scratching.
1. Remove the two bolts from the top of the garage door opener.
2. Align the rail and the styrofoam over the sprocket. Cutthe tape from the rail, chain, and
styrofoam.
3. Fasten the rail with the previously removed bolts.
4. Position the chain around the garage door opener sprocket.
5. Install the sprocket cover:Insertthe back tab in the slot. Squeeze the cover slightlyand insert
the front tab in the slot on the mounting plate.
Washered Bolts 5/16"-18x1/2"
(Mounted in the garage door opener)
2 Tighten the Chain
1. Loosen the inner nutand lock washer on the trolley threaded shaft.
2. Tighten the outer nut until the chain is a 1/2 inch above the base of the rail at the midpoint of
the rail.
3. Re-tighten the inner nut.
Slack in the chain is normal when the door is closed. No readjustment is necessary.
NOTE: Sprocket noise can result if the chain is too loose. During future maintenance, ALWAYS pull the
emergency release handle to disconnect the trolley before adjusting the chain.
1/2"