Chamberlain 248735S 3/4 HP User Manual

3

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.

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.

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.

During assembly, installation and adjustment of the 
opener, instructions will call for hand tools as illustrated 
below.

Pliers

Wire Cutters

Claw Hammer

Hack Saw

Screwdriver

Adjustable End Wrench

Sockets and Wrench
1/2", 5/8", 7/16", 9/16"
and 1/4"

Drill

Tape Measure

Stepladder

Pencil

Drill Bits
3/16", 5/16"
and 5/32"

Carpenter’s
Level (optional)