Chamberlain LiftMaster Security + 3270 1/2 HP Manuel D'instructions page 3

Preparing your garage door
Before you begin:
• Disable locks.
• Remove any ropes connected to garage door.
• Complete the following test to make sure your garage
door is balanced and is not sticking or binding:
1. Lift the door about halfway as shown. Release the
door. If balanced, it should stay in place, supported
entirely by its springs.
2. Raise and lower the door to see if there is any
binding or sticking.
If your door binds, sticks, or is out of balance, call a
trained door systems technician.
Sectional Door
Stepladder
One-Piece Door
Carpenter's
Level (optional)
Drill
1/2" and 7/16"
Sockets and Wrench
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 installing
and operating garage door opener to avoid
entanglement.
To prevent damage to garage door and opener:
• ALWAYS disable locks BEFORE installing and
operating the opener.
• ONLY operate garage door opener at 120V, 60 Hz
to avoid malfunction and damage.
Tools needed
During assembly, installation and adjustment of the
opener, instructions will call for hand tools as illustrated
below.
Pencil
Tape Measure
3/16",
5/16" and
5/32" Drill Bits
Screwdriver
3
Hack Saw
Wire Cutters
Claw Hammer
Pliers
Adjustable End Wrench