Possible Cause: System has not been balanced.
Corrective Action: Request a copy of the balance report and review against the specified CFM requirements.
Possible Cause: System losses are less than design.
Corrective Action: Adjust or change sheaves as necessary based on the system losses as installed. Adjust dampers or otherwise add pressure to the system.
Possible Cause: There are leaks in the system.
Corrective Action: Check ductwork for leaks or open ducts and repair.
Possible Cause: Fan speed is higher than design.
Corrective Action: Adjust the belt and sheaves as necessary for the installed conditions.
Possible Cause: VFD requires adjustment.
Corrective Action: Check fan set points. Adjust PID settings for desired performance.