LiftMaster 3840 3840 Manual - Page 15

INSTALLATION STEP 6 Hang the Opener Three representative installations are shown. Yours may be different. Hanging brackets should be angled (Figure 1) to provide rigid support. On finished ceilings (Figure 2 and Figure 3), attach a sturdy metal bracket to structural supports before installing the opener. This bracket and fastening hardware are not provided. 1. Measure the distance from each side of the motor unit to the structural support. 2. Cut both pieces of the hanging bracket to required lengths. 3. Drill 3/16" pilot holes in the structural supports. 4. Attach one end of each bracket to a support with 5/16"-18x1-7/8" lag screws. 5. Fasten the opener to the hanging brackets with 5/16"-18x7/8" hex bolts, lock washers and nuts. 6. Check to make sure the rail is centered over the door (or in line with the header bracket if the bracket is not centered above the door). 7. Remove the 2x4. Operate the door manually. If the door hits the rail, raise the header bracket. NOTE: DO NOT connect power to opener at this time. To avoid possible SERIOUS INJURY from a falling garage door opener, fasten it SECURELY to structural supports of the garage. Concrete anchors MUST be used if installing ANY brackets into masonry. Figure 1 Structural Supports Measure Distance Bolt 5/16"-18x7/8" Lock Washer 5/16" Nut 5/16"-18 Lag Screws 5/16"-18x1-7/8" Figure 2 Bracket (Not Provided) Hidden Support - FINISHED CEILING - Lag Screws 5/16"-18x1-7/8" Bolt 5/16"-18x7/8" Lock Washer 5/16" Nut 5/16"-18 (Not Provided) Bolt 5/16"-18x7/8" Lock Washer 5/16" Nut 5/16"-18 HARDWARE SHOWN ACTUAL SIZE Lag Screw 5/16"-18x1-7/8" Hex Bolt 5/16"-18x7/8" Nut 5/16"-18 Lock Washer 5/16" Figure 3 Lag Screws 5/16"-18x1-7/8" Bolt 5/16"-18x7/8" Lock Washer 5/16" Nut 5/16"-18 FINISHED CEILING (Not Provided) Bolt 5/16"-18x7/8" Lock Washer 5/16" Nut 5/16"-18 15