Vents VK 250 U centrifugal fan Ø 250 MM / 1080 M³

A 250 mm centrifugal duct fan with a built-in thermostat and speed module, rated 1080 m³/h.

The VK 250 U regulates itself on temperature. In a growing setup it is worth knowing what that control does not look at.

The module controls on temperature, not humidity

The built-in module measures one thing: the temperature of the air in the duct. If it rises too far the fan steps up; as it falls, the fan backs off. That is exactly what you want for heat removal.

Humidity plays no part in that control. For a grow space that is a real limitation, because moisture matters at least as much as heat there, and the two do not always move together.

The clearest example is the dark period. The lamps go off, the temperature falls, and the module obediently returns to your minimum setting. Meanwhile the plants keep transpiring while the air cools, so relative humidity actually climbs. The fan does less at precisely the moment you would want it doing more.

There are two ways to handle that. The simple one: set the minimum speed high enough that adequate air keeps moving even without a trigger, and accept that you are using the control mainly for peaks. The complete one: use the standard version with a separate climate controller driving on temperature and humidity, with a probe you hang at canopy height yourself.

For extraction in a shed, garage or commercial unit, where heat is the problem and humidity is not, this version is exactly enough and saves two devices on the wall.

Construction

The front panel carries a speed dial, a thermostat dial and two indicator lights. Beneath it the standard VK 250: centrifugal impeller with backward-curved blades, external rotor motor with self-recovering thermal cut-out, bearings for at least 40,000 running hours and a plastic housing that does not corrode.

Technical Specifications:

• Power draw: 173 W
• Current: 0.76 A
• Connection: 250 mm
• Volume flow: 1080 m³/h
• Control: built-in module, thermostat plus speed control
• Controls on: air temperature in the duct
• Does not control on: humidity
• Thermal cut-out: recovers by itself
• Bearing life: at least 40,000 running hours
• Construction: corrosion-resistant plastic, IPX4, class II

Frequently asked questions

Can I have it control on humidity?
No, the module looks only at temperature. Humidity control needs a separate climate controller.

What should I do during the dark period?
Set the minimum speed high enough that adequate air keeps moving without a trigger.

When is this version ideal?
Where heat is the problem and humidity is not: a shed, garage or commercial unit.

What is the difference from the VK 250 Q U?
That one has the quiet motor and delivers 865 m³/h. This one delivers 1080 with the same control module.