FAQ - Multifan (Fan)

Frequently asked questions

How slow can the fan run? »»

Technically the motors can be slowed down to 0 RPM. However, to obtain a stable curve with frequency control a motor can be reduced until approximately 30% of the maximal speed. The minimum of 30% is based on obtaining a minimal steady airflow, undependable of local conditions (open doors, etc.)

Is it possible to reverse air flow? »»

Yes, instructions for reversing the air flow are included with the motor. We strongly recommend to have the reverse only carried out by a qualified technician.

Makes it sense to reverse the air flow? »»

An impeller is suitable in 1 direction: the air output is than 100%. Reversing the airflow results in only 50% air capacity or less in certain circumstances

What is the difference between the old style fans and the Q-line? »»

Major difference is the frame material (from aluminum to plastic), the mounting of the supports and the lower noise level.

What does the ”Q-line” stand for and why switched Multifan over to the Q-line? »»

Q stands for quality, chosen to express the unique features of the Multifan line. Because of market demands and request (cleaning, hygiene, weight, stacking, noise) Vostermans switched over from aluminum to plastic frames

What are the standard operating temperatures of the Multifan fans »»

The standard fans are suitable for an ambient temperature of 40°C/104 F to -36°C/-32 F. On customer demand a special range of fans could be available for higher temperatures.

Are there grills available for all fans? »»

A wide range of grills is available for intake and exhaust side of the fans. Check the sales department for details.

Is it possible to change the pitch of the blade by the customer? »»

With the G- and K-system it is possible, because of the use of position rings by technical trained persons. With the C-system it is not possible (only during production at Vostermans Ventilation)

Is it practical to change the position of the blades in the field? »»

Changing the position of the blade may influence the balancing of the impeller, the wrong angle can create overload of the motor or the motor can no longer be controllable.

Can the Multifan impeller mount to standard motors? »»

Yes, only if the power consumption of the impeller matches the emitted power (shaft output power) of the motor. Of course, dimensions and power consumption need to fit.

Can a standard impeller fit onto Multifan motors? »»

Yes, only if the power consumption of the impeller matches the emitted power (shaft output power) of the motor. Of course, dimensions and power consumption need to fit.

What is the mounting torque of the Q-frames and impeller? »»

Lists of torques are available.

What are the standards for measuring fan noise? »»

The measurement is made 7 meters away from fan (in free field condition). The fan is in a vertical position, the sound measuring instrument is located at the fan level, 7 meters away from the motor side of fan (intake air side), 45° left or right of the fan. The sound is measured in decibels; on the A scale (dbA).

How do I reverse the airflow on a Vostermans Ventilation fan? »»

The standard air direction on Vostermans Ventilation fans is from the motor end to the impeller, stated another way, the air intake is on the motor side. Reversing the air flow is a simple two part process:

For a single phase motor, remove the motor end cap (only after disconnecting the power supply). Switch connections of the brown and red wires that come out of the motor winding. This reverses the motor. For a three phase motor, reverse any two of the three external lead-in connections to reverse the motor.
Take the complete impeller off of the motor shaft. The impeller hub is two pieces. Remove the bolts that hold the two pieces together, separate the hub and turn each blade 180 degrees. The hub is notched so each blade only fits in one of two positions.
Put everything back together properly.
Vostermans Ventilation recommends only well qualified and equipped installers to reverse the air flow of the fans.

Vostermans Companies is not responsible for inaccurate or incomplete data. In case of any questions and/or remarks please contact .