Chamberlain WHISPER DRIVE HD900D - Manual (Page 15)

15
ONE-PIECE DOOR WITHOUT TRACK
A 2x4 on its side is convenient for setting an ideal door-to-rail
distance.
• Remove foam packaging.
• Raise the opener onto a stepladder. You will need help at this
point if the ladder is not tall enough.
• Open the door all the way and place a 2x4 on its side on the
top section of the door beneath the rail.
• The top of the door should be level with the top of the motor
unit. Do not position the opener more than 4" (10 cm) above
this point.
INSTALLATION STEP 4
Position the Opener
Follow instructions which apply to your door type as illustrated.
SECTIONAL DOOR OR ONE-PIECE DOOR WITH TRACK
A 2x4 laid flat is convenient for setting an ideal door-to-rail
distance.
• Remove foam packaging.
• Raise the opener onto a stepladder. You will need help at this
point if the ladder is not tall enough.
• Open the door all the way and place a 2x4 laid flat on the top
section beneath the rail.
• If the top section or panel hits the trolley when you raise
the door, pull down on the trolley release arm to disconnect
inner and outer sections. Slide the outer trolley toward the
motor unit. The trolley can remain disconnected until
Installation Step 12 is completed.
To prevent damage to garage door, rest garage door opener
rail on 2x4 placed on top section of door.
Header
Bracket
Top of Door
2x4 is used to determine
the correct mounting height
from ceiling.
Rail
2x4 is used to determine
the correct mounting height
from ceiling. Door
ENGAGED RELEASED
Trolley
Release Arm