Installation Considerations; Ducted Inlet Installations - Greenheck FumeJet FJC-300 Installation, Operation And Maintenance Manual

Installation Considerations

Installations with inlet configurations that deviate from this manual may result in reduced fan performance. Restricted
or unstable flow at the fan inlet can cause pre-rotation of incoming air or uneven loading of the fan wheel yielding
large system losses and increased sound levels. Free discharge or turbulent flow in the discharge ductwork will also
result in system effect losses. Refer to the following diagrams for the most efficient installation conditions.

Ducted Inlet Installations

Inlet Duct Turns - Installation of a duct turn or elbow
too close to the fan inlet reduces fan performance
because air is loaded unevenly into the fan wheel. To
achieve full fan performance, there should be at least
three fan wheel diameters between the turn or elbow
and the fan inlet.
3 fan wheel
diameters
Turning
Vanes
®
POOR
GOOD
Inlet Spin - Inlet spin is a frequent cause of reduced
fan performance. The change in fan performance is a
function of the intensity of spin and not easily defined.
The best solution is proper duct design and airflow
patterns. Turning vanes reduce the effects of inlet spin.
Turning
Vanes
FumeJet
POOR
GOOD
®
Fume Exhaust Fans 5