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Adjustment of Scroll Dampers
Figure 26. Scroll damper adjustment
Two sets of scroll dampers are provided in the housing of the
twin 15" x 6" supply fan to allow control of air volume to each
fan wheel. At the factory, these dampers are fully closed
unrestricting airflow. If fan paralleling occurs, correction can
be made by loosening the adjustment screw on top of the fan
housing (see Figure 26) and slightly lowering the rod until air
distribution between the fans is even.
Adjustment Assembly
Scroll Damper
Adjustment of Supply Fan Thrust Restraints
Thrust restraints are provided with all twin 15" supply fans.
After the spring mounts have been adjusted for level opera-
tion, the thrust restraints should be checked. With the fan off,
the adjustment nuts should be set so the spring is slightly
compressed against the angle bolted to the fan housing
frame. Refer to Figure 27. When the fan is turned on, the fan
will move back to a level position and the thrust restraint
springs will compress.
Figure 27. Thrust restraint adjustment
Thrust Restraint Adjustment
(
with fan off )
1. Loosen jam nuts “A”.
2. Turn nut “C” until spring cup and washer contact thrust restraint
angle.
3. Turn nut “B” until spring is compressed by two turns of nut “B”.
4. Tighten jam nuts “A”.
Washer
Thrust Restraint
Angle
Spring Cup
Fan
Bulkhead
Jam Nut
“A”
Detail A
Nut
“C”
Nut
“B”
Fan Housing
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