Apparatenbouw B.V.

Lovense Kanaaldijk 61
5013 BJ Tilburg
013 - 542 50 02

Poor Performance

Fan rotation incorrect
Refer to Vibration section. An easy way to change rotation on most 3-phase motors is to reverse any two motor leads.

Abrupt turn in the duct close to the fan discharge or air pre-spin caused by ductwork elbows at the inlet.
Install turning vanes or elbow splitters in the duct. If air performance is still inadequate, the discharge position may have to be changed.
If fan has an Inlet Volume Control (IVC), is it properly installed?
Be sure the IVC is installed with pre-spin of the air in direction of wheel rotation when the IVC is partially closed.

Off-center wheel
This can occur on double width, double inlet fans. Center the fan between the inlet cones to avoid overloading one side of the wheel while starving the other.

Fan horsepower unexpectedly low
Correct one or more of the following conditions:
a. Air pre-spin into the fan inlet
b. Fan drive sheaves set for too low a fan speed
c. Resistance to airflow, such as caused by a closed damper, much higher
   than calculated

Fan horsepower unexpectedly high
Be sure fan speed is not too high. Fan may be operating without ductwork at low resistance so that too much air is flowing. The fan may be handling ambient air when it was originally intended for hot, less dense air. Fan may be running backwards.