LiftMaster GH GT- Logic 4 Installation Manual - Page 10

TROLLEY TYPICAL INSTALLATION INSTALL THE HEADER BRACKET The trolley operator is generally mounted over the center of the door. However, off center mounting may be required due to interfering structures or location of door stile / top section support. Typically, the operator may be mounted up to 24 inches off center on torsion spring doors. Extension springs require center mounting. 1 Close the door. Mark the center of the door with a vertical line, extend the line onto the ceiling. 2 Open the door to the highest point of travel mark 4 inches above the highest point of travel. 3 Center the header bracket on the vertical center line and the horizontal line. 4 Drill the pilot holes for the header bracket. WARNING To prevent possible SERIOUS INJURY or DEATH: CAUTION • Header bracket MUST be RIGIDLY fastened to structural support on header wall or ceiling, otherwise 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 door, springs, cables, pulleys, brackets, or their hardware, ALL of which are under EXTREME tension. • ALWAYS call a trained door systems technician if door binds, sticks, or is out of balance. AVERTISSEMENT 5 Fasten the header bracket with appropriate hardware (not provided). ATTENTION 1 2 Typical installation - Trolley 5 ADVERTENCIA PRECAUCIÓN 3 4" 4 10