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© FANTECH
2016
INSTALLATION, WIRING DIAGRAMS & FAN TROUBLE SHOOTING
FAN TROUBLE SHOOTING
N
1.0 GENERAL
Problem
Possible Cause
Recommended Action
1.1 Motor Noise
Firstly determine if the noise is electrical
or mechanical.
If the noise doesn't stop instantly, but
runs down with the motor, the problem is
more likely to be mechanical, generally
the bearings; see Mechanical section
below:
If the motor is switched off and the noise
stops instantly the problem is more likely
to be electrical; see Electrical section
pages
N-12/14
.
2.0 MECHANICAL
Problem
Possible Cause
Recommended Action
2.1 General Fan Noise
The fan could be running in stall.
Check the actual fan performance
against the fan curve to determine where
on the curve it is operating. If it is to the
left of the peak pressure point the fan is
generally in stall. If in stall see if the
ductwork can be modified to eliminate
high pressure loss sections.
Low amps could indicate the fan is in
stall. Reduce the pitch angle.
2.2 Bearing noise varying from a
'dry' rumble to a squeal
Improper greasing.
Check the bearings are packed with the
correct grade and amount of grease.
If the bearings are of the sealed-for-life
type replace them.
The bearings may be loose on the shaft
or bearing support.
Tighten the adaptor sleeve or collar.
The bearings have not been properly
tensioned
Re-tension as required
2.3 Rough lumpy sound.
The bearings may have brinelled.
Brinelling occurs when the fan is vibrated
during transit or through ground vibration
when stored. This causes the bearing to
vibrate at a single point and therefore
indenting the bearing race.
Problems with brinelling usually occur
shortly after a fan is installed.
Replace the bearings. To avoid brinelling
the fan impeller should be rotated
frequently, at least daily.
Excessive belt tension.
Check and adjust the belt tension.
2.4 Shaft seal squeal
The seals may have dried out.
The seals may require lubrication or may
be misaligned.
2.5 Air noise
Air noise can be generated from a
number of sources such as grilles,
bends, badly designed duct fittings,
excessive duct velocities etc.
Check the duct design is such it does
not generate turbulence and therefore
noise. An attenuator may be needed to
resolve the problem.
2.6 Vibration
The impeller may be out of balance.
Site balancing may be practical but, if
not, remove the impeller and balance.
The shaft may be bent.
The shaft will have to be replaced.
Impeller may be worn as a result of
handling abrasive or corrosive materials.
The impeller will have to be replaced.
Material such as dust or grease could be
sticking to the fan blades.
Clean the impeller blades. This should be
done on a regular basis if dust and/or
grease is constantly present in the air
being handled.
The impeller may have been damaged
by loose material in the duct system.
Depending on the level of damage the
impeller may have to be replaced