Vents - VK 125 Centrifugal Inline Fan Ø125 mm

A 125 mm centrifugal duct fan rated 370 m³/h, in a plastic housing.

The VK 125 is the same bare version as the 100 mm model, one size up. Choosing between the two is rarely about the 80 cubic metres per hour between them.

100 or 125

Decide on your ducting rather than on airflow. If there is already a 100 mm penetration or run in place, moving up to 125 costs you a reducer, and that reducer squeezes the gain straight back out.

If you are still free, 125 mm is the calmer choice. The same volume of air travels more slowly through a wider bore, and slower air makes less noise past bends and edges. You hear that in the room, even where the airflow figures barely differ.

A third consideration is the filter. Carbon filters are made per size, and the choice in 125 mm is generally wider than in 100 mm. So look ahead to what you want to hang behind it before committing to the fan.

Why there is plastic around it

The housing is UV-resistant plastic. The UV part seems odd for a component hanging indoors, but it mainly says something about how the material ages: plastic not treated for weathering turns brittle over the years and cracks around screw holes and flanges.

More important day to day is that plastic does not rust. Extracted air from a growing space is warm and humid, which is exactly the combination thin sheet steel eventually loses to.

The motor

The drive is a sealed external rotor motor: the rotor turns on the outside around the fixed winding, so the impeller sits directly on the rotating part and no separate shaft and coupling are needed. It runs long-life bearings and carries thermal protection within the motor itself.

Technical Specifications:

• Power draw: 79 W
• Current: 0.34 A
• Duct size: 125 mm
• Airflow: 370 m³/h
• Impeller: centrifugal, backward-curved blades
• Drive: sealed external rotor motor
• Bearings: long-life
• Protection: thermal protection in the motor
• Material: UV-resistant plastic
• Supplied with: mounting bracket
• Mounting angle: your choice

Frequently asked questions

Should I take the 100 or the 125?
Choose on the size of your ducting. A reducer costs you the gain you were after with the larger size.

Is plastic weaker than steel?
For this application it is the practical choice: it does not rust in damp extract air.

What is an external rotor motor?
A motor whose rotating part is on the outside, so the impeller can sit directly on it.

Does it have a controller on board?
No. This is the version without a control module. Look at the U version for that.