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CHICAGO D/36A Centrifugal Fan Operating And Maintenance Instructions page 3

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2. Shim the fan support points before tightening foundation bolts. Do not
distort or twist the equipment. Duct connections should be smooth
and straight. Elbows and other transitions should be located at least
five wheel diameters from fan inlet and outlet (see AMCA Publication
201 for further details). Flexible connections should be used at inlet
and discharge. The fan should never support or restrain any duct
weight or force.
3. Make sure the power is locked "OFF".
4. Check wheel-to-inlet clearance to make sure it has not shifted during
shipment or handling. There should be approximately equal radial
clearance all around. Rotate wheel by hand to check that it runs free.
5. If the wheel is striking, correct it by loosening the hub set screws and
reposition the wheel on the shaft, or loosen the motor mounting bolts
(for Arrangement 4 fans) and realign the wheel to the inlet so it does
not hit. Retighten all set screws and bolts and turn by hand again.
6. If the fan wheel is fastened with a taper-lock bushing and the wheel
must be shifted, follow this procedure:
a. Match mark the bushings and the hub so they can be reinstalled in
exactly the same relative position so as to not unbalance the wheel.
b. Remove all bolts from the bushings.
c. Insert two bolts in the threaded holes in the bushing. (Note that one
bolt is left over and not used in the demounting.)
d. Tighten bolts alternately until bushing is loosened in hub. If
bushing does not loosen immediately, lightly tap hub while applying
torque to the bolts.
5. From inside the plenum, push the drive end of the drive shaft through the
plenum shaft hole and through the inboard bearing bracket. With the
shaft end halfway to the outboard bracket, slip one bearing on the shaft.
Then push the wheel-shaft assembly all the way through and install the
drive bearing. Use mounting hardware as shown below. Both bearings
are the same
6. With the wheel temporarily pushed flush against the inside plenum wall,
the shaft can be centered on the hole, the inboard bearing mounting
bolts tightened and then the outboard bearing mounting bolts tightened.
This locates the shaft perpendicular to the plenum wall and fan drive
panel. Check level shaft.
If the fan is vertically mounted with inlet down, block the wheel and
shaft in place with wood blocking to prevent damage. Do not block
bearings to shaft yet.
7. Slide the shaft through the bearings and locate its drive end flush with
the end of the motor shaft. Make sure the bearing locking collar is in
position and tighten set screws to the bearing manufacturer's torque
levels. See bearing manufacturer's instructions enclosed for details.
8. Slide the wheel along the shaft and position it a distance from the
plenum wall, determined by the thickness of the insulation or the gap
designed in the plenum. This dimension is not critical. Any extra length
of shaft may extend through the hub without harm.
9. Install the inlet cone loosely on the housing or plenum structure,
attaching it only at four points until final adjustments are made. Move
the wheel along the shaft so that it slightly overlaps the inlet cone.
Position the inlet cone to be concentric to the wheel opening with
equal spacing in a radial direction all around. The inlet cone can be
firmly fastened at this time.
On a Heat Fan or a fan not operating at maximum static pressure, it is
satisfactory to have an axial gap between the wheel and inlet cone of
3/16" to 5/8" depending upon the fan size. This axial gap can be
adjusted by moving the wheel closer to or farther away from the cone.
Tighten wheel set screws.
Recheck the wheel cone to inlet cone clearance.
1 . Mount the adjustable motor base on the drive panel gusset as shown
in the illustration. Mount the motor on the adjustable motor base and
adjust the base height for the approximate center distance of the V-belt
being used.
To reinstall the taper-lock bushing in the wheel hub, position the bush-
ing to align the match marks and insert the three mounting bolts
through the unthreaded bushing holes into the hub. Alternately tighten
the bolts. When tightening, the bolts should be turned down equally to
the initial Torque requirement given below. Then tighten the bolts
progressively one-half turn per bolt to the Second Torque setting.
Finally, the bolts should be tightened in small increments to the Final
Torque settings.
Initial Torque*
Size
Bushing
Alum.
Steel.
Q & R
57
120
P
36
84
*Torque values shown are inch lbs. and apply when both components
are either aluminum or steel. If either component is aluminum, use
values for aluminum. Values for steel are for Grade 5 hardware.
Check bushing to verify type or refer to bushing box sent with the fan.
7. Check the motor wiring and fusing in accordance with the National
Electrical Code and local requirements. Follow wiring diagram on the
motor nameplates.
8. Chicago Blower requires that all appurtenances, including ductwork or
stacks, which are attached to the fan inlet or outlet, be independently
supported, unless prior approval has been obtained from Chicago
Blower. Excess dead loads or wind loads can distort the fan housing
causing misalignment and possible failure. Flexible connections are
also necessary to prevent duct expansion or movement from adding
loads to the fan.
11 Loosely install the fan and motor sheaves and the belts. Tighten the
fan sheave first, then align the motor sheave to the fan sheave. The
fan and motor shafts must be parallel. See V-belt Drive section of this
manual for sheave alignment and installation.
12.If the fan handles air above 300° F, install the shaft-cooling wheel by
centering it in the space between the inboard bearing and drive panel.
Two self-tapping bolts clamp the cooler to the shaft.
13.Install all shaft, cooling wheel, bearing guards and belt guards as
required.
14.If the fan has been provided with an Inlet Volume Control (IVC), it is
mounted in the inlet cone and no further adjustments are required
except to hook up the operating lever to the Customer's Control.
The IVC should be checked for correct rotation. Looking at the IVC
from the inlet side with IVC blades half closed, the blades should pre-
spin the entering air in the same direction as the fan wheel is rotating.
NOTE: For High Temperature Applications – The fan should not be
shut off until the airstream temperature is below 150°.
Second Torque*
Final Torque*
Alum.
Steel
Alum.
Steel.
108
240
228
348
72
132
132
192

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