WHEEL AND INLET CONE OVERLAP DETAIL
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
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. Remove all bolts from the bushing.
b. Insert two bolts in the threaded holes in the bushing. See Detail.
(Note that one bolt is left over and not used in demounting.)
c. Tighten bolts alternately until bushing is loosened in hub. If the
bushing does not loosen immediately, lightly tap hub while
applying torque to the bolts.
To reinstall the taper-lock bushing in the wheel hub, clean bushing,
hub and shaft of all oil, lacquer, grease or dirt, 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.
9. The run-in period should be at least eight hours. Check the
motor bearings a minimum of once each hour during this peri-
od. Do not overgrease motor bearings. Consult your motor
Take vibration readings at the motor bearings. Adhere to
these limits. Velocity Limits in inches/second – Normal: 0.15; Alarm:
0.22; Shutdown: 0.50. Readings are based at operating speed (filter-
To insure long life and trouble-free service, frequently check motor
bearing lubrication. See the motor manufacturer’s instructions
packed with the fan. Should excessive vibration develop, check the
1. Build-up of dirt or foreign material on the wheel.
2. Loose bolts on motor, fan housings or foundation.
3. The wheel eroding or corroding..
4. Wheel set screws are loose.
5. Foreign matter may have entered fan causing damage to
6. Vibration may be coming from a source other than the fan.
Stop the fan and determine if the vibration still exists. Disconnect
the motor from the fan and operate it by itself to determine if it pro-
7. Proper clearance between the wheel and the inlet.
A preventive maintenance schedule is a necessity for extending fan life.
Establish a lubrication schedule based on time periods suggested in
lubrication instructions by motor manufacturers.
After approximately one (1) month of operation, all base, hub, motor, etc.
bolts should be checked.
Potentially damaging conditions are often signaled in advance by
change in vibration and sound. A simple, regular audio-visual inspection
of fan operation leads to correction of the condition before expensive
damage occurs. Vibration levels should be checked by an approved
technician using electronic balancing equipment.
If air handled by the fan contains corrosive, erosive or sticky materials,
fan should be shut down regularly for inspection, cleaning and recondi-
tioning of interior parts.
If the fan is to remain idle for an extended period, protect motor and
exposed surfaces. Follow the motor manufacturer’s recommendations
for storage and rotate the shaft by hand several revolutions each month.
Certain operating conditions reduce the built-in
strength of the fan impeller and may cause unsafe operation. It is the
user’s responsibility to inspect for these conditions as frequently as
necessary and to make corrections as required. Failure to comply with
the following limits voids the Chicago Blower Corporation warranty.
Maximum Safe Speed and Temperature:
Operation exceeding maxi-
mum safe RPM and temperature even for a short time causes over-
stressing or fatigue cracking of the impeller resulting in unsafe condition.
Maximum safe speed and maximum safe temperature are shown on fan
assembly drawings, catalogs or order acknowledgement.
Q & R
Check bushing to verify type or refer to the bushing box located in
the plastic envelope.
7. Check the motor wiring and fusing in accordance with the
National Electrical Code and local requirements. Follow wiring dia-
gram on the motor nameplates.
8. Check motor bearing lubrication. They were lubricated at the fac-
tory, but recheck, and if required use a good grade motor lubricant.
Consult your motor instruction book.
D1900 Series Only
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.