Centrifugal Inline Fans
11
®
PROBLEM
CAUSE
CORRECTIVE ACTION
Excessive noise
or vibration
Wheel imbalance
Clean all dirt off wheel. Check wheel balance, rebalance in
place if necessary.
Bad bearings
Replace.
Belts too tight or too loose
Adjust tension, see Figure 11.
Wheel improperly aligned and
rubbing
Center wheel on inlet, see Figure 7.
Loose drive or motor pulleys
Align and tighten. See Pre Start-Up Checks, pages 6-7.
Foreign objects in wheel or
housing
Remove objects, check for damage or unbalance.
Reduced airflow
System resistance too high
Check system: Proper operation of backdraft or control
dampers, obstruction in ductwork, clean dirty filters.
Unit running backwards
Correct as shown in Figure 8.
Excessive dirt buildup on wheels Clean wheel.
Improper wheel alignment
Center wheel on inlets, see Pre Start-Up Checks and Figure 7.
WARNING
Before taking any corrective action, make certain unit
is not capable of operation during repairs.
Troubleshooting
