4
Vektor-CD Centrifugal Laboratory Exhaust
®
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 procedure). Replace worn
belts or sheaves.
Bearings
Replace defective bearing(s). Lubricate bearings.
Tighten collars and fasteners.
Wheel unbalance
Clean all dirt off wheel. Check wheel balance, replace if
necessary.
Low CFM
Fan
Check wheel for correct rotation. Check blade position
of bypass air plenum (BAP) damper, increase fan speed.*
Duct system
Higher pressure than design. Filters need replacement.
High CFM
Fan
Decrease fan speed.
Duct system
Increase BAP damper blade open position. Resize
ductwork. Access door, filters, dampers not installed.
Static pressure wrong
Duct system has more
or less restriction than
anticipated
Change obstructions in system. Use correction factor
to adjust for temperature/altitude. Adjust set point used
to control BAP damper modulation. Resize ductwork.
Clean filters/coils. Change fan speed.*
High horsepower
Fan
Check rotation of wheel. Reduce fan speed.
Duct system
Resize ductwork. Check proper operation of isolation
and bypass dampers. Check filters and access doors.
Fan doesn’t operate
Electrical supply
Check fuses/circuit breakers. Check for switches turned
off or disconnected. Check for correct supply voltage.
Drive
Check for broken belts. Tighten loose pulleys.
Motor
Assure motor is correct horsepower and not tripping
overload protector.
Overheated bearing
Lubrication
Check for excessive or insufficient grease in the bearing.
Mechanical
Replace damaged bearing. Relieve excessive belt
tension. Align bearings. Check for bent shaft.
Excessive vibration
Belts
Adjust tightness of belts. Replacement belts should be a
matched set.
System unbalance
Check alignment of shaft, motor and pulleys. Adjustable
pitch pulleys with motors over 15 hp are especially
prone to unbalance. Check wheel balance, rebalance if
necessary.
* Always check motor amps and compare to nameplate rating. Excessive fan speed may overload the motor and result in
motor failure. Do not exceed the maximum cataloged rpm of the fan.
Troubleshooting
Model — General description of fan
S/N
— Serial Number assigned by Greenheck,
which is a unique identifier for every unit
Mark — Customer supplied identification
MODEL
S/N
MARK
®
Unit Identification
The tag below is an example of an identification label on the fan. The information provides general details
about the fan, as well as containing specific information unique to the unit. When contacting your Greenheck
representative with future needs or questions, please have the information on this label available.
Tags are mounted in an area which is clearly visible—usually on the side of the fan housing.
