Aerovent IM-977 - Manual (Page 6)

6 Aerovent IM-977
Fan Troubleshooting Chart
PROBLEM POSSIBLE CAUSES
EXCESSIVE VIBRATION 1. Wheel or sheaves loose on shaft.
2. Belts too loose or too tight.
3. Out of balance wheel.
4. Excessive buildup of dirt/dust on wheel.
5. Bent shaft.
6. Weak mounting base for fan.
7. Fan mounting bolts loose.
8. Loose or worn bearings.
9. Bearing or drive misalignment.
10. Mismatched belts.
11. Structures not cross-braced (wall fans).
12. Curb not flat and level.
EXCESSIVE HORSEPOWER 1. Wheel rotating in wrong direction.
2. Fan speed higher than design.
3. Wheel rubbing on inlet venturi.
4. Worn fan bearings.
TOO LITTLE AIR 1. Restricted fan inlet or outlet.
2. Wheel rotating in wrong direction.
3. System is more restrictive (more static pressure) than expected.
4. Fan speed lower than design.
5. Inlet or outlet screens clogged.
6. Dampers or shutters not opening.
TOO MUCH AIR 1. Fan speed higher than design.
2. System is less restrictive (less static pressure) than expected.
FAN DOES NOT OPERATE 1. Wrong voltage.
2. Electricity turned off or not wired properly.
3. Loose pulleys.
4. Blown fuses.
5. Tripped overload protector.
6. Broken belts.
EXCESSIVE NOISE 1. Wheel or sheaves loose.
2. Bearing or drive misalignment.
3. Accumulation of material on wheel.
4. Worn or corroded wheel.
5. Wheel out of balance.
6. Wheel hitting housing.
7. Bent shaft.
8. Bearings need lubrication.
9. Loose bearing bolts.
10. Loose or worn bearings.
11. Mismatched belts.
12. Belts too loose or too tight.
13. Belts oily or dirty.
14. Belts worn.
15. Loose fan mounting bolts.
16. Rattle of components in high velocity airstream.
17. Electrical noise.
18. Noise from high velocity air system.
19. Vibrating parts not isolated from building.
20. Vibrating ductwork.
It is recommended that the users and installers of this shipment familiarize themselves with AMCA Publication #201,
“Fans and Systems” and publication #202, “Troubleshooting” which are published by Air Movement and Control
Association, 30 West University Drive, Arlington Heights, Illinois 60004.