Problem Cause Corrective Action
Excessive Noise
Wheel Rubbing Inlet
Adjust wheel and/or inlet cone. Tighten wheel hub or bearing
collars on shaft.
V-Belt Drive
Tighten sheaves on motor/fan shaft. Adjust belt tension. Align
sheaves properly (see page 4). Replace worn belts or sheaves.
Replace defective bearing(s). Lubricate bearings. Tighten
collars & fasteners.
Wheel Unbalance
Clean all dirt off wheel. Check wheel balance, rebalance in
place if necessary.
Fan Check wheel for correct rotation. Increase fan speed.*
Duct System See page 4.
High CFM
Fan Resize ductwork. Access door, filters, grills not installed.
Duct System
Change obstructions in system. Use correction factor to adjust
for temperature/altitude. Resize ductwork. Clean filters/coils.
Change fan speed.*
Static Pressure
Duct system has more
or less restriction than
Check rotation of wheel. Adjust fan speed.
High Horsepower
Fan Check rotation of wheel. Reduce fan speed.
Duct System
Resize ductwork. Check proper operation of face and bypass
dampers. Check filters and access doors.
Fan Doesn’t Operate
Electrical Supply
Check fuses/circuit breakers. Check for switches off. Check for
correct supply voltage.
Drive Check for broken belts. Tighten loose pulleys.
Assure motor is correct horsepower and not tripping overload
Overheated Bearing
Lubrication Check for excessive or insufficient grease in the bearing.
Replace damaged bearing. Relieve excessive belt tension.
Align bearings. Check for bent shaft.
NOTE: Always provide the unit model and serial numbers when requesting parts or service information.
* Always check motor amps and compare to nameplate rating. Excessive fan speed may overload the motor
and result in burnout.
455308 • SWB / SFB / SFD, Rev. 6, June 2011 Copyright 2011 © Greenheck Fan Corporation
Greenheck warrants this equipment to be free from defects in material and workmanship for a period of one year from the
shipment date. Any units or parts which prove to be defective during the warranty period will be replaced at our option
when returned to our factory, transportation prepaid. Motors are warranted by the motor manufacturer for a period of one
year. Should motors furnished by Greenheck prove defective during this period, they should be returned to the nearest
authorized motor service station. Greenheck will not be responsible for any removal or installation costs.
As a result of our commitment to continuous improvement, Greenheck reserves the right to change specifications without notice.
Greenheck Centrifugal Utility Fan catalog provides additional
information describing the equipment, fan performance,
available accessories, and specification data.
AMCA Publication 410-96, Safety Practices for Users and
Installers of Industrial and Commercial Fans, provides
additional safety information. This publication can be
obtained from AMCA International, Inc. at