Installation, Operation & Maintenance Manual
IM-995
29
Troubleshooting Guidelines
Use current safety practices when investigating fan or system
performance problems. General safe practices and performance
410 and 202, respectively. Fan application and field measurement
Below is a list of possible areas to check when air or sound values do
of these common causes.
Air Capacity Problems
1. Resistance of the system is not at design rating. If resistance is
lower than expected, both airflow and horsepower may be up.
If resistance is higher than anticipated, air volume will be down.
2. Fan speed is not at design speed.
3. Air density is not at the design value. Also check air performance
measurement techniques/procedures.
4.
filters.
5. Impeller mounted improperly or is rotating in reverse.
6. Parts of the system or fan have been damaged or need cleaning.
Noise Problems
1. Air performance is incorrect and the fan is not at design point
of operation. Fan is being forced to operate in an unstable flow
region near peak or to the left of the peak of the curve.
2.
3. Supply voltage high or inconsistent supply frequency. Adjustable
frequency controllers can generate motor noise.
4. Objects that are installed in a high velocity airstream can
generate noise. This includes flow sensors, turning vanes, etc.
5. Poor fan inlet conditions.
6. Acoustics or sound measurement procedure incorrect.
Vibration Problems
1.
2.
3. Foreign material attached to rotating components.
4.
5. Broken, loose or missing set screws.
6. Loose bolts.
7. Vibration transmitted by another source.
8. Water accumulating in airfoil blades.
9. Fan is operating in stall or unstable flow region.
Motor Problems
1. Incorrect wiring.
2. Speed of fan too high.
3. Parts improperly installed; binding.
4. Bearings improperly lubricated.
5. WR
2
capability of motor too low for application.
6. Protection devices may be improperly sized.
7.
8. Is cabling and grounding correct?
Drive Problems
1. Belts improperly tensioned.
2.
3. Coupling lubrication.
Vibration Guidelines
Condition
Fan
Applicaon
Category
Rigidly Mounted
mm/s (in./s)
Flexibly Mounted
mm/s (in./s)
Start-up
BV-3
Alarm
BV-3
Shutdown
BV-3
Most fans manufactured by Twin City Fan & Blower are factory
balanced prior to shipment. Certain high horsepower, large or
unusual voltage fans, may not be run as an assembly due to power
constraints, however the rotors have been dynamically balanced.
Installation variables, handling and movement of the fan during
shipment may cause the rotating assembly to shift. Balance should
be checked once the fan is installed. If a final trim balance is
required, it is the end user's responsibility to bring the fan back to
factory specifications. Final trim balancing is not the responsibility
of Twin City Fan & Blower. Refer to the Vibration Guidelines table
below.
NOTICE
Twin City Fan
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