Chamberlain 480LMC User manual

To avoid possible SERIOUS INJURY to fingers from moving
garage door opener:
• Be sure power is not connected to the garage door opener
BEFORE installing the 480LM mounting kit.
• ALWAYS keep hand clear of chain and sprocket while
operating opener.
• Securely attach chain cover BEFORE operating.
Figure 2
Figure 1
Models 480LM & 480LMC
Alternate Mounting Kit
1
2
3
4
5
INSTALLATION
1. Disassemble kit and remove foam pad (attached to
sprocket hub). Discard foam pad.
2. Attach the T-bracket to the motor unit using the
self-threading screws (Figure 1).
NOTE: The T-bracket will be above the existing mounting
bracket.
3. Attach sprocket with larger bore (1-1/4") to the motor
shaft of the opener. Position the sprocket so that the
screws are facing up and are accessible when
attached to the torsion bar (Figure 2).
4. Tighten both sides of the sprocket screws equally to
secure the sprocket to the motor unit (12-14 ft./lbs.
of torque). Securely tighten set screw.
CARTON INVENTORY
1T-bracket
21-1/4" Sprocket with Collar and Screws
31" Sprocket with Collar and Screws
4Chain
5Cover Assembly
NOT SHOWN
Hardware: 1/2" Screw (1),
#10 Self-Threading Screw (2),
and 1-1/2" Hex Head Screw (2)
Instructions
5
(provided with opener)

Figure 5
Figure 6 Figure 7
INSTALLATION
5. Attach sprocket with the smaller bore (1") to the
torsion bar making sure that the screws are on the
side closest to the garage door (Figure 3).
NOTE: Do not tighten sprocket at this time.
6. Place the chain on the sprocket located on the
torsion bar (Figure 4).
7. Attach the sprocket located on the motor unit shaft to
the chain. Secure the motor unit to the wall using the
hex head screws (Figure 5).
NOTE: Ensure that the chain is perpendicular to the bar
and not too tight.
8. Tighten both screws of the sprocket on the torsion
bar equally to secure the sprocket to the bar
(12-14 ft./lbs. of torque). Securely tighten set screw.
You may need to rotate the chain to make the
screws accessible.
9. One side of the chain cover will have an indentation
that will fit into the middle of the motor unit sprocket.
This side should be put on first (Figure 6).
10. Position the remaining cover over the other side so
that it encloses the chain and sprocket assembly.
The covers will snap into place. Secure them by
screwing them together using the 1/2" screw
(Figure 7).
11. Rotate chain to ensure smooth travel. Adjust, if
necessary.
12. Refer to Installation Step 2 of the owner’s manual for
further instructions.
Figure 4
Figure 3