Set The Force - Chamberlain Liftmaster Security+ 3900PLD Owner's Manual

ADJUSTMENT STEP 2

Set the Force

The force setting measures the amount of force
required to open and close the door.
1. Push the purple button twice to enter into the Force
Adjustment Mode. The LED will flash quickly.
2. Push the door control or programmed remote control.
The door will close (DOWN).
3. Push the door control or programmed remote control
again. The door will open (UP).
4. Push the door control or programmed remote control a
third time to close the door (DOWN).
The LED will stop flashing when the force has been
programmed.
The door must travel through a complete cycle, up and
down, in order for the force to be set properly. If the
garage door opener cannot open and close the door fully,
inspect the door to ensure that it is balanced properly and
is not sticking or binding.
If the door is not stopping exactly where you would like it,
repeat Program the Travel Limits.
Without a properly installed safety reversal system, persons
(particularly small children) could be SERIOUSLY INJURED or
KILLED by a closing door.
• NEVER learn forces or limits when door is binding or
sticking. Repair door first
• Too much force on door will interfere with proper operation
of safety reversal system.
• After ANY adjustments are made, the safety reversal system
MUST be tested. Door MUST reverse on contact with 1-1/2"
high (3.8 cm) object (or 2x4 laid flat) on floor.
Figure 1
LED
Purple
Button
Figure 3
18
Figure 2
Black
Button
Push Purple button
twice to enter
unit into Force
Adjustment Mode
BLACK
PURPLE