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INLINE FANS FAQs

Answers to your most frequently asked questions about Greenheck inline fans.

Q:
Q:Can a solid state speed control be used on a belt drive fan?
A:
A:Greenheck does not offer solid-state speed controls on belt drive fans because the motors must be a permanent split capacitor (PSC) or shaded pole type. These motor types are not used on belt drive fans because they have very low starting and running torque. Belt drive fans have added torque requirements due to bearings, belts, and pulleys, all which hinder the ability of the motor to start the fan or even keep it running if the voltage is dialed down on the speed control.
Q:
Q:Can belt drive inline axial and centrifugal fans be mounted with the motors at 3 or 9 o'clock?
A:
A:Yes. Greenheck's inline axial and centrifugal fan Models BSQ and TCB are very versatile in mounting options. However, keep in mind that when the fan is mounted with the motor on the side, the motor weight may cause uneven loading on the isolators. This uneven loading can be overcome by mounting the fan on a set of rails that extend beyond the fan on both sides so that the weight of the fan and motor are carried between the outboard isolators.
Q:
Q:Can centrifugal inline fans be mounted outside?
A:
A:Models SQ or BSQ are not recommended for outdoor mounting. These fans are not weathertight.
Q:
Q:Can SP, CSP, SQ, or BSQ model fans be mounted vertically?
A:
A:Models SP and CSP can be vertically mounted, but the backdraft damper on the "B" design may not close depending on the orientation. Models SQ and BSQ can mount in any orientation, except the larger/heavier motors need external support when the motor is on the side. 
Q:
Q:What factors prevent fans from not performing as specified?
A:
A:

There are numerous reasons why fans fail to perform as specified. But first, it is important to understand what defines acceptable performance. According to AMCA Publication 200, a fan installed in a ventilation system should expect a tolerance of +/- 7.5% for flow (cfm). In other words, a fan which produces 1,000 cfm in a lab environment should provide a volume flow rate of 925 to 1,075 cfm when installed in a properly designed ventilation system.

Volume flow rates which fall below this range are typically the results of variances in system static pressure or mechanical problems with the fan. Common symptoms include:

Obstructions in the duct system - closed dampers, closed registers, dirty filters, clogged coils

Obstructions in the fan inlet - elbows to close to the inlet, walls too close to the inlet

Duct design - improperly designed turning vanes, leaks in supply or exhaust ducts

Fan related - impeller running backwards, fan speed too low, impeller dirty or clogged, clearances between inlet cone and wheel cone are incorrect.