LiftMaster JHDC Installation Manual - English French Spanish - Page 13

TDC Trolley 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 the door stile / top section support. Typically, the operator may be mounted up to 24 inches (60.1 cm) 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 (10.1 cm) 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. 5. Fasten the header bracket with appropriate hardware (not provided). 1 WARNING To prevent possible SERIOUS INJURY or DEATH: • Header bracket MUST be RIGIDLY fastened to the structural support on the header wall or ceiling, otherwise the door might NOT reverse when required. DO NOT install the header bracket over drywall. • Concrete anchors MUST be used if mounting the 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 an Authorized Service Technician if door binds, sticks, or is out of balance. 5 3 2 4" 4 13