LiftMaster 8550 8550 Manual - Page 7

1 Determine the header bracket location To prevent possible SERIOUS INJURY or DEATH: • Header bracket MUST be RIGIDLY fastened to structural support on header wall or ceiling, otherwise garage door might NOT reverse when required. DO NOT install header bracket over drywall. • Concrete anchors MUST be used if mounting header bracket or 2x4 into masonry. • NEVER try to loosen, move or adjust garage door, springs, cables, pulleys, brackets, or their hardware, ALL of which are under EXTREME tension. • ALWAYS call a trained door systems technician if garage door binds, sticks, or is out of balance. An unbalanced garage door might NOT reverse when required. • DO NOT enable the Timer-to-Close functionality if operating either one-piece or swinging garage doors. To be enabled ONLY when operating a sectional door. NOTE: If you are installing the garage door opener on a one-piece door, visit www.liftmaster.com for installation instructions. 1.1 Close the door and mark the inside vertical centerline of the garage door. 1.2 Extend the line onto the header wall above the door. You can fasten the header bracket within 4 feet (1.22 m) of the left or right of the door center only if a torsion spring or center bearing plate is in the way; or you can attach it to the ceiling when clearance is minimal. (It may be mounted on the wall upside down if necessary, to gain approximately 1/2" (1 cm). If you need to install the header bracket on a 2x4 (on wall or ceiling), use lag screws (not provided) to securely fasten the 2x4 to structural supports. 1.3 Open your door to the highest point of travel as shown. Draw an intersecting horizontal line on the header wall 2" (5 cm) above the high point. This height will provide travel clearance for the top edge of the door. NOTE: If the total number of inches exceeds the height available in your garage, use the maximum height possible, or refer to page 8 ceiling installation. Header Wall 2" (5 cm) Track Highest Point of Travel Door Unfinished Ceiling Header Wall 2x4 Vertical Centerline of Garage Door 2x4 OPTIONAL CEILING MOUNT FOR HEADER BRACKET Structural Supports Level (Optional) Sectional door with curved track 7