Chamberlain PD300DM Manuale Utente

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

2

1

Stepladder

Pencil

Drill Bits 
3/16", 5/16" 
and 5/32"

Carpenter’s
Level (optional)