LiftMaster 3275 3275 Manual - Page 4

Planning Identify the type and height of your garage door. Survey your garage area to see if any of the conditions below apply to your installation. Additional materials may be required. You may find it helpful to refer back to this page and the accompanying illustrations as you proceed with the installation of your opener. SECTIONAL DOOR INSTALLATION Horizontal and vertical reinforcement is needed for lightweight garage doors (fiberglass, steel, aluminum, door with glass panels, etc.). See page 20 for details. Header Wall FINISHED CEILING Support bracket & fastening hardware is required. See page 12. Slack in chain tension is normal when garage door is closed Extension Spring OR Torsion Spring Motor unit Vertical Centerline of Garage Door OR One-Piece Door-Extension Spring Wall-mounted Door Control Header Wall Access Door Door Track Safety Reversing Sensor Gap between floor and bottom of door must not exceed 1/4" (6 mm). Safety Reversing Sensor ONE-PIECE DOOR WITHOUT TRACK Header Wall Slack in chain tension is normal when garage door is closed FINISHED CEILING Support bracket & fastening hardware is required. See page 12. Motor unit Wall-mounted Door Control ONE-PIECE DOOR WITH TRACK Slack in chain tension is normal when garage door is closed Access Door Access Door Safety Reversing Sensor Gap between floor and bottom of door must not exceed 1/4" (6 mm). Safety Reversing Sensor 4 Safety Gap between floor and Reversing Sensor bottom of door must not Safety Reversing exceed 1/4" (6 mm). Sensor