LiftMaster 8550 8550 Manual - Page 2

Preparation Safety Symbol and Signal Word Review This garage door opener has been designed and tested to offer safe service provided it is installed, operated, maintained and tested in strict accordance with the instructions and warnings contained in this manual. When you see these Safety Symbols and Signal Words on the following pages, they will alert you to the possibility of serious injury or death if you do not comply with the warnings that accompany them. The hazard may come from something mechanical or from electric shock. Read the warnings carefully. Mechanical Electrical When you see this Signal Word on the following pages, it will alert you to the possibility of damage to your garage door and/or the garage door opener if you do not comply with the cautionary statements that accompany it. Read them carefully. Check the Door 1. Disable locks and remove any ropes connected to the garage door. 2. Lift the door halfway up. Release the door. If balanced, it should stay in place, supported entirely by its springs. 3. Raise and lower the door to check for binding or sticking. If your door binds, sticks, or is out of balance, call a trained door systems technician. 4. Check the seal on the bottom of the door. Any gap between the floor and the bottom of the door must not exceed 1/4 inch (6 mm). Otherwise, the safety reversal system may not work properly. 5. The opener should be installed above the center of the door. If there is a torsion spring or center bearing plate in the way of the header bracket, it may be installed within 4 feet (1.2 m) to the left or right of the door center. See installing the Header Bracket section. Torsion Spring Extension Spring Tools Needed To prevent possible SERIOUS INJURY or DEATH: • ALWAYS call a trained door systems technician if garage door binds, sticks, or is out of balance. An unbalanced garage door may not reverse when required. • NEVER try to loosen, move or adjust garage door, door springs, cables, pulleys, brackets or their hardware, ALL of which are under EXTREME tension. • Disable ALL locks and remove ALL ropes connected to garage door BEFORE installation and operating garage door opener to avoid entanglement. 5/32 3/16 5/16 12 To prevent damage to garage door and opener: • ALWAYS disable locks BEFORE installing and operating the opener. • ONLY operate garage door opener at 120 V, 60 Hz to avoid malfunction and damage. 1/2 5/8 1/4 7/16 9/16 7/16 2