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The fan kit, which you have purchased, is a rotating piece of equipment

and can become a source of danger to life or cause injury if not properly

applied. The maximum operating temperature or speed for which this fan

is designed must not be exceeded. These limits are given in our catalog

or on Chicago Blower Corporation drawings.

Personnel who will operate these fan kits, or those who will perform main-

tenance thereon, must be given this manual to read and warned of the

potential hazards of this equipment.

This bulletin contains general recommendations, but specific require-

ments may apply to given installation. Such requirements are outlined in

federal, state and local safety codes. Strict compliance with these codes,

and strict adherence to these installation instructions are the responsibil-

ity of the user.


Housing stiffeners or frame should provide rigidity and support to the

housing. Housings are often supplied less stiffeners to provide flexibility

for various installations. See Fan Kit Bulletins –SAF (single width), -DAF

(double width), or –PFD as required for recommended bracing schedule.

Additional support may also be required. Supports should not restrict air

flow to the inlet or discharge of the fa


Many airfoil wheels supplied by Chicago Blower have weep holes sup-

plied as standard. The weep holes are small diameter holes located on

the top skin of the blade near the trailing edge or integrally formed into

the blade. Weep holes are designed to allow condensation, which can

accumulate within an airfoil blade when at rest, to be expelled when the

wheel is running. When the wheel is running centrifugal forces of the

rotating wheel force the condensation out the weep hole. Without the

weep holes the condensation can adversely affect the balance integrity of

the wheel. This condensation phenomenon typically occurs in applica-

tions where the system conditions i.e. temperature or density varies from

that of the ambient surroundings. If high humidity is involved in your appli-

cation contact Chicago Blower for recommendations.


All Chicago Blower wheels are precision balanced at the factory to ISO

1940/ANSI S2.19 Quality Grade G6.3 or better; however, when a preci-

sion balanced wheel is installed onto a shaft, there are many other

aspects to consider before the system will run with minimal vibration.

Some of these include, but are not limited to, fit-up the wheel hub to the

shaft, especially if bushings are used, residual imbalance of a motor,

residual imbalance of the sheaves used for belt drive, soft foot on the

motor caused by improper shimming of the fan bearings, alignment of the

shaft coupling, and alignment of the fan bearings. With all of these items

playing a part in the overall vibration of the assembly, it may seem daunt-

ing to commission a system with low vibration and minimal maintenance

that will operate for years.

To minimize system vibration the wheel must be “phase balanced” to the

rest of the components in the rotating system. What is phase balance?

Phase balance is performing a touch up or trim balance to any compo-

nent of the rotating system including the wheel. Depending on whether

the wheel or other rotating component has one or two planes, phase bal-

ance can be carried out in either single plane or two plane mode. Also,

a phase balance does not mean that the wheel itself is out of balance;

rather, phase balance of an otherwise perfectly balanced wheel is usual-

ly easiest because it is typically the largest and heaviest rotating element

of the system. It is easier to apply the correction weights to the outer

diameter of the wheel to compensate for the imbalance of the rotating

system. There are times where the imbalance of the system is minimal

and no phase balance is required for smooth operation.

Once the wheel has been phase balanced to the rotating system, the

wheel must be visually inspected periodically for any signs of wear or

material build up that can cause imbalance. In material handling sys-

tems, even a small amount of material that has eroded or corroded the

wheel can affect the balance of that wheel. If this were to happen, the

wheel would have to be phase balanced to the rotating system again to

correct the balance for the missing material. Eventually, eroded or cor-

roded wheels will not be able to be rebalanced and will need to be

replaced entirely to avoid total failure. In addition, rotating systems that

handle clean air can also have eventual balance problems if not

watched closely. Fine dirt and dust can build up on the wheel blades

causing imbalance again. Occasionally, the wheel must be cleaned to

restore the balance.

It is also recommended that vibration checks be conducted on the fan

and motor bearings. Fans that have been tested for vibration with

phase balanced wheels normally run smoothly at first and over time

begin to show signs of increasing vibration levels. Steadily increasing

vibration levels are indicators that the wheel or other rotating element

has gone out of balance for the reasons stated above, or the bearings

have begun to wear and will need to be replaced.


Fan Kit components are available separately or in virtually any combi-

nation including wheel, inlet cone, inlet volume control damper, hous-

ing, shaft, bearings and cooling wheel. Housings are to be mounted so

the inlets are free from obstructions and should be centered within

enclosures for double inlet fans. Bearing pedestals are to be installed

so that the bearings can be shimmed for proper centerline height.

If mounting within an oven or enclosure, provide an opening in the wall

for shaft to pass through. Additional space at wall may be required

when installing a cooling wheel and cone. Installation of a cooler cone

may also require the use of a cylindrical section to retain insulation and

maintain proper depth of over wall.


1. Move components to the final mounting location. Be sure to follow

the handling instructions given above.

2. Remove skid, crates, and packaging.

3. Move lower housing/supports to mounting location.

4. Level and shim if required. Do not distort or twist the equipment. Bolt

into place.

5. If bearing support is separate from housing:

a. Set bearing pedestal on bolts.

b. Never distort bearing pedestal by forcing into position espcially if

mounting to a non-level surface. Shim under pedestal as required.

c. Check bearing centerline height. Adjust centerline height to

match centerline of housing. High temperature applications may

require the housing centerline to set lower when cold so that

it will be centered when hot due to thermal expansion.

d. Measure from housing to bearing pedestal to bring into square

with housing.

e. Bolt into position.

6. Shaft and wheel assembly

a. Clean protective coating off shaft with solvent. Do not touch clean

areas of shaft with hands. Perspiration or oils from hands can

cause rust or pitting over time.

b. Remove keys from shaft.

c. Clean inside of bore. Bores may have paint overspray and dirt

from shipment which must be removed prior to mounting the

wheel and/or bushing. Make sure hub set screws or bushing

mounting bolts are loosened as to not interfere when inserting

shaft into bore.

7. Continue to 8, 9 or 10 based on arrangement.

8. Arrangements 1, 8 or 9

a. Insert shaft into wheel from back side of wheel.

b. Typically shaft should protrude out face of hub approximately 1-1/2".

Put key into keyway and lightly tighten wheel set screws. Do not

torque set screws at this time.

c. Install bearings onto shaft. Do not tighten bearing set screws at