Twin City Centrifugal Roof & Wall Exhausters - IM-4050 - Manual (Page 8)

8 Twin City IM-4050
Fan Troubleshooting Chart
PROBLEM POSSIBLE CAUSES
FAN DOES NOT OPERATE 1. Wrong voltage.
2. Electricity turned off or not wired properly.
3. Tripped overload protector.
4. Blown fuses.
5. Loose pulleys.
6. Broken belts.
TOO LITTLE AIR 1. Wheel rotating in wrong direction.
2. Fan speed lower than design.
3. System is more restrictive (more static pressure) than expected.
4. Restricted fan inlet or outlet.
5. Inlet or outlet screens clogged.
6. Filters (if applicable) are dirty or clogged.
TOO MUCH AIR 1. Fan speed higher than design.
2. System is less restrictive (less static pressure) than expected.
EXCESSIVE HORSEPOWER 1. Wheel rotating in wrong direction.
2. Wheel rubbing on inlet venturi.
3. Fan speed higher than design.
4. Worn fan bearings.
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.
EXCESSIVE VIBRATION 1. Wheel or sheaves loose on shaft.
2. Wheel out of balance.
3. Excessive buildup of dirt/dust on wheel.
4. Belts too loose or too tight.
5. Mismatched belts.
6. Bent shaft.
7. Bearing or drive misalignment.
8. Loose or worn bearings.
9. Fan mounting bolts loose.
10. Weak mounting base for fan.
11. Structures not cross-braced (wall fans).
12. Curb not flat and level.
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 the Air Movement and Control
Association (AMCA), 30 West University Drive, Arlington Heights, Illinois 60004. www.amca.org