LiftMaster 3255 3255 Manual - Page 8

INSTALLATION STEP 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. Header Wall Unfinished Ceiling 2x4 Vertical Centerline of Garage Door 2x4 OPTIONAL CEILING MOUNT FOR HEADER BRACKET Structural Supports Level (optional) Installation procedures vary according to garage door types. Follow the instructions which apply to your door. 1. Close the door and mark the inside vertical centerline of the garage door. 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 (see page 9) 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 as shown here and on page 9. 3. Open your door to the highest point of travel as shown. Draw an intersecting horizontal line on the header wall above the high point: • 2" (5 cm) above the high point for sectional door and one-piece door with track. • 8" (20 cm) above the high point for one-piece door without track. 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 9 for ceiling installation. Header Wall 2" (5 cm) Track Highest Point of Travel Door Sectional door with curved track Header Wall 8" (20 cm) Door Highest Point of Travel Jamb Hardware Door Header Wall Track 2" (5 cm) Highest Point of Travel One-piece door with horizontal track Header Wall 8" (20 cm) Door Highest Point of Travel Pivot One-piece door without track: jamb hardware One-piece door without track: pivot hardware 8