LiftMaster LJ8950W LJ8950W Manual - Page 8

Installation Dead Shaft Door Requirements For dead shaft door installations the door sprocket is attached to the door drum which spins to move the door. DRUM CONDITON The door drum must not be bent or damaged. If bent, the drive chain may not align to the sprocket and could derail the chain. If the drum does not have mounting holes which align to the door sprocket, use the door sprocket as a template to drill holes in the proper location. SPRING CLEARANCE The internal door springs must not interfere with the door sprocket installation. Inspect for interference by sliding the door sprocket on the door shaft to the drum and aligning the mounting holes. Sprocket mounting holes should not be obstructed by the door spring for a minimum depth of 3" (7.6 cm). Some door manufacturers require the door to be modified with an extra drum on the end of the door barrel to provide an unobstructed platform for door sprocket installation. DOOR CLEARANCE The dead shaft door must not have more than a 2" (5 cm) space from the curtain edge to the drum. The door operator comes with a selection of spacers that can be used together to provide a maximum 3" (7.6 cm) of spacing. MINIMUM SIDE CLEARANCE A minimum of 11" (27.9 cm) clearance on the outside of the door guide is required for outside mounting. A minimum of 3.75" (9.5 cm) clearance is required for inside mounting. If the door brackets interfere with door operator installation, move the door brackets away from the door assembly to provide room in the desired location. Remove existing door sprocket. You MUST use the door sprocket provided in order for the door operator to function correctly. Door Sprocket Mounting Pattern Use 3 holes 120˚ Apart 2" (5 cm) Max Inset 2.5" (6.3 cm) Min. Clearance 3" (7.6 cm)Bolt Clearance Drum Door Shaft Spring Door Bracket 11" (27.9 cm) Min. Clearance Outside Mounting 3.75" (9.5 cm) Min. Clearance Inside Mounting Door Guide 8