Trane QFNA-IOM-1 - Manual (Page 30)

Vibration and Noise
Most noise and vibration problems
are caused by components being
worn, misaligned, or loose. These
conditions can usually be found by
observation. The problem is solved
by replacement, realignment or
tightening of the parts involved.
Other Noise and Vibration
Sources
1. Wheel unbalanced
2. Drive components unbalanced
3. Bearing defective, contaminated
or not lubricated adequately
4. Set of “unmatched” belts in use
5. Foreign material in fan housing
6. Electrical hum from motor
7. Air velocity higher than design
8. Fan operating in surge
9. Isolation system not functioning
properly
10.Shaft bent
HP Too High
1. Fan speed above design
2. Static pressure above design
Low CFM
1. Leaks or obstructions in duct
system
2. Access door open
3. RPM too low
4. System resistance higher than
design
5. Variable inlet vanes partially
closed
High CFM
1. System resistance below design
2. RPM too high
Overheated Bearing
Bearings on high speed fans can run
as high as 75 ° F above ambient.
They may feel very warm with no
problem being present. This is
especially true immediately after
lubrication when it is normal for
bearings to run somewhat hot while
they purge excess grease.
High Temperatures
Abnormally high temperatures can
be caused by the following
conditions:
1. Overgreasing
2. Foreign material in bearing
3. Excessive belt tension
4. Poor alignment
5. Bent shaft
6. Damaged or worn bearing
7. Inadequate lubrication
30 QFNA-IOM-1
Troubleshooting