Brake Adjustment; Clutch Adjustment And Auxiliary Reversal System - Chamberlain APT Owner's Manual

BRAKE ADJUSTMENT

The solenoid brake is adjusted at the factory and should not need
additional adjustment for the life of the brake assembly.
Replace brake assembly when necessary. Refer to the illustration
for identification of components for the solenoid type brake
system.
CLUTCH ADJUSTMENT AND
AUXILIARY REVERSAL SYSTEM
The Auxiliary Reversal System is designed to protect the door
and motorized operator. It is NOT a substitute for a safety sensing
device. The Auxiliary Reversal System works in tandem with the
adjustable clutch to detect if a closing door runs into or comes
across an obstruction. If an obstruction is met and causes the
clutch to slip, the Auxiliary Reversal System will return the door
to the full open position when closing or stops the door when
opening.
1. Remove cotterpin from nut on the clutch shaft.
2. Back off clutch nut until there is very little tension on the
clutch spring.
3. Tighten clutch nut gradually until there is just enough tension
to permit the operator to move the door smoothly but to allow
the clutch to slip if the door is obstructed. When the clutch is
properly adjusted, it should generally be possible to stop the
door by hand during travel.
4. Reinstall cotterpin.
A D J U S T M E N T
Solenoid
To prevent possible SERIOUS INJURY or DEATH, install
reversing sensors when the 3-button control station is out of
sight of the door or ANY other control (automatic or manual) is
used. Reversing devices are recommended for ALL
installations.
Cotterpin
10
Cotterpin
Release Lever
WARNING
CAUTION
Clutch Pad
Adjusting Nut
Spring
Washer
Clutch Pulley
Brake Assembly
Brake
Plate Assembly
Clutch Plate