®
MBD-10
1
Document 476321
MBD-10
1½ in. or 2 in. Standoff Brackets,
Manual Quadrant, and Cable Operator
Installation, Operation and Maintenance Manual
Please read and save these instructions for future reference. Read carefully before attempting to assemble, install,
operate or maintain the product described. Protect yourself and others by observing all safety information. Failure
to comply with these instructions will result in voiding of the product warranty and may result in personal injury
and/or property damage.
5
6
7
3
4
2
1
Quadrant
Pointer
Item
Qty
Description
Part Number
1
1
Manual Quadrant
475679
2
1
Bolt
415034
3
1
Flat washer
416206
4
1
Hex nut
415455
5
1
Wing nut
415885
6
1
Axle pin
454136
7
1
Axle clip
451890
Tools Required:
Hammer
5
⁄
16
in. driver
Electric drill
9
⁄
16
in. drill bit
7
⁄
16
in. wrenches (2)
Installation Instructions Without Standoff Bracket
1. Install the damper in the duct. Place fasteners so that they do not interfere with operation of the blades. The end
of the blade that has the lances will accept the quadrant drive pin. Place that side of the damper on the side of
the duct where the quadrant is to be located.
2. Cut a hole through the duct over the lanced blade axle bearing. The hole should be large enough for the axle pin
to slide through (approximately
9
⁄
16
in. diameter).
3. Slide the axle pin through the quadrant. Align the quadrant pointer with the blade as shown and then insert the
pin into the damper blade lances.
4. Pound the axle pin into the damper blade until the quadrant is approximately ¾ in. (19mm) away from the duct.
5. Rotate the quadrant and blade until the blades are at the full closed position. (The quadrant pointer will be
approximately perpendicular to the centerline of the duct).
6. While holding the quadrant and blade in the closed position and using the end of the outer quadrant arc as a
guide, drill a ¼ in. (6mm) diameter hole through the duct. Drill the hole at the end of the arc that is furthest from
the quadrant pointer.
7. Rotate the quadrant out of the way and insert the bolt from the inside of the duct. Secure the bolt to the duct
using the hex nut.
8. Rotate the quadrant and blade back and position the quadrant over the bolt. Apply the flat washer and wing nut
onto the bolt.
9. Pound the axle pin into the blade until the axle clip is within
1
⁄
8
in. (3mm) of the quadrant.
10. Using the quadrant lever, cycle the damper while checking for proper operation. Verify that the blade is free
floating within the frame. Resolve any interference issues that prevent smooth operation.
11. Set the damper blade to the desired position and tighten the wing nut.
