Chamberlain 3850 Manuale Utente

Safety 
Reversing Sensor

Support bracket & 
fastening hardware
is required.
See page 12.

 — — —        — — —        — — 

Header Wall 

 

FINISHED CEILING 

Torsion 
 Spring 
 
 

Extension 
 Spring 
 

OR  

Safety
Reversing Sensor

Gap between floor and bottom 
of door must not exceed 1/4" (6 mm)  

Access
Door

Wall-
mounted
Door 
Control

Horizontal and vertical reinforcement
is needed for lightweight garage doors
(fiberglass, steel, aluminum, door with
glass panels, etc.). See page 19 for details.

Motor Unit 

Vertical
Centerline
of Door

 

4

Identify the type and height of your garage door. Survey your garage area to see if any of the conditions below apply to
your installation. Additional materials may be required. You may find it helpful to refer back to this page and the
accompanying illustrations as you proceed with the installation of your opener.

FINISHED CEILING

Support bracket
& fastening
hardware is required.
See page 12.

Safety 
Reversing Sensor 

Header 
Wall 

Access  
Door 

Safety  
Reversing Sensor 

Gap between floor and bottom of 
door must not exceed 1/4" (6 mm) 

Wall- 
mounted 
Door  
Control 

Motor Unit

Access
Door

Safety Reversing Sensor

Gap between floor and bottom of door 
must not exceed 1/4" (6 mm).

Safety Reversing Sensor