Chamberlain 841LM Manual Download Page 1

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AUTOMATIC GARAGE DOOR LOCK

Model 841LM

Before you begin

Installation

For use on Residential Garages with an Entry Door Only. Install On Sectional Doors with Torsion
Assemblies Only.

This product is intended for installation only by trained garage door technicians.

Please read and save these instructions with the instruction manual of the garage door opener.
Up to two locks can be installed per compatible garage door opener.

This automatic garage door lock is compatible with LiftMaster

garage door openers with a

Security Shield.

Carton Inventory:

Automatic Garage Door Lock, Template, 1/4"-20x1/2" Screws (2), 33' (10 m) Wire

Tools needed:

Stepladder, Drill, 5/16" and 3/4" Drill Bits, Tape Measure, Screwdriver

UNPLUG THE GARAGE DOOR OPENER AND DISCONNECT THE BATTERY (IF APPLICABLE)
BEFORE PROCEEDING. REMOVE ANY MANUAL LOCKS FROM THE GARAGE DOOR.
FOR WALL MOUNT GARAGE DOOR OPENERS CONSULT THE GARAGE
DOOR OPENER MANUAL FOR INSTALLATION STEPS.

Attach template (provided) to track.

TIP

: The second roller from the bottom is ideal for

most installations.

Drill holes as marked on template.

Fasten automatic garage door lock to the outside of
the garage door track with the 1/4"-20x1/2" screws.

Run wire (provided) from automatic garage door
lock to garage door opener. Use insulated staples
(not provided) to secure wire in several places.

NOTE

: If you are going to cut the wire you will

need to reconnect wire using a wire nut. Do not
tape the ends together. The lock is polarized and
requires you reconnect black to black and white to
white wires.

Plug the connector into one of the lock terminals
on the garage door opener.

NOTE

: To install a second automatic garage door

lock, repeat installation steps on the opposite side
of the garage door.

To prevent possible SERIOUS INJURY or DEATH from a closing gate or door:
• Automatic Garage Door Lock MUST be installed per the owner’s manual.
• Be sure to DISCONNECT ALL ELECTRIC AND BATTERY POWER to the garage door opener

BEFORE installing the garage door lock.

• The door MUST be in the fully opened or closed position BEFORE installing the garage door lock.
• Be sure to DISASSEMBLE and REMOVE any manual door locks that might be currently installed.

Approx. 3"
(7.6 cm)

Lock
terminals

™

WARNING:

This product can expose you to chemicals including lead, which are known to

the State of California to cause cancer or birth defects or other reproductive harm. For more
information go to

www.P65Warnings.ca.gov