Vents VK 250 Q R centrifugal fan Ø 250 MM / 865 M³

A 250 mm centrifugal duct fan with a quiet motor, rated 865 m³/h.

The VK 250 Q R is the quiet version in the largest size. Of all the Q models in this range, this is the one where the letter earns most.

Why the Q counts most at this size

Ventilation noise comes mainly from air velocity: the harder air has to travel through your duct, the more you hear. On a 100 mm fan moving 250 m³/h that noise exists, but it is small enough to ignore.

At this size a multiple of that passes through. The standard version does 1080 m³/h, this one 865. Those two hundred-odd cubic metres per hour mean lower velocity through the same 250 mm cross-section, and you hear that in a way the small sizes never raise.

On top of that, a large fan usually hangs in a larger space, and larger spaces are more often spaces with people in them: a shed, a cellar, a commercial unit. Five decibels of difference registers there.

The trade is the same as on the smaller Q models: you give up airflow. So work out your space first and check whether 865 m³/h is enough with your filter and duct length included. If that is tight, take the standard version and turn it down; a fan with headroom running gently is quieter than a quiet fan working flat out.

Construction

Outside the motor everything matches the standard VK 250: centrifugal impeller with backward-curved blades, balanced during assembly, external rotor motor with a thermal cut-out that recovers by itself, bearings for at least 40,000 running hours, and a plastic housing that does not corrode. Free positioning, brackets included.

Technical Specifications:

• Power draw: 108 W
• Current: 0.47 A
• Connection: 250 mm
• Volume flow: 865 m³/h
• Motor: quiet version, asynchronous, external rotor
• Fan type: centrifugal, backward-curved blades
• Thermal cut-out: switches back in by itself once cooled
• Bearing life: at least 40,000 running hours
• Construction: corrosion-resistant plastic, IPX4, class II
• Positioning: free, brackets included

Frequently asked questions

How much quieter is it than the standard?
Vents publishes no separate decibel figure for the Q version, so we quote none. What is certain is 865 against 1080 m³/h through the same cross-section.

Or the standard with a controller instead?
If 865 is tight for your space, yes. A larger fan running gently is quieter than a quiet one working flat out.

Does it fit the same ducting?
Yes, both 250 mm and the same housing.

Is there a version with a thermostat?
Yes, the VK 250 Q U pairs this motor with the built-in control module.