Vents - TT Pro 250 RV Mixed-Flow Inline Fan Ø250 mm

A 250 mm inline fan with a mixed-flow impeller and a two-speed switch, rated 1100 or 1400 m³/h at 44 to 51 dB(A) measured at three metres. Draws 125 to 177 watts.

The TT Pro 250 RV is the largest in the range. The step up from the 200 is bigger than the difference in collar size suggests, and so is the machine.

From 200 to 250: what you gain and what it costs

In airflow you go from 1040 to 1400 m³/h on high, roughly a third more air. In consumption you go from 108 to 177 watts, so that extra third of air costs about two thirds more electricity. That is how fans work: the more air you ask for, the less proportional the bill.

The surprise is in the noise. Vents rates the 250 at 44 to 51 dB(A) at three metres, against 45 to 52 for the 200. The larger fan is not louder, because it moves its air with a bigger impeller rather than with more air velocity, and velocity is where most of the sound comes from.

In size the difference is substantial. The 250 measures 323 by 287 by 383 mm and weighs 7.8 kilos, against four kilos for the 200. That is nearly double, and it changes how you hang it.

The practical conclusion: move to the 250 if you genuinely need the airflow, or if the alternative is running a 200 flat out continuously. A 250 on low delivers more air than a 200 on high, draws comparable power and makes less noise.

Hanging eight kilos

At this weight the fan belongs on structure that carries it, not on the ducting and not on a single screw in plasterboard. Any orientation is allowed, so it can stand, lie or hang, but spread the weight across two points.

Hang it loose in straps or on rope hangers rather than bolting it down tight. A fan fixed rigidly to structure passes its vibration straight into it, and then you hear it through the wall while the unit itself stays comfortably inside its 51 dB(A).

For servicing, the motor and impeller block lifts out of the casing on clamps. At this size that is not a luxury: cleaning the impeller without dismantling the whole run saves real work.

Technical Specifications:

• Duct size: 250 mm, actual diameter 247 mm
• Airflow: 1100 m³/h on low, 1400 on high
• Noise: 44 to 51 dB(A), measured at three metres
• Power draw: 125 to 177 W
• Speed: 1955 to 2440 rpm
• Dimensions: 323 x 287 x 383 mm
• Weight: 7.8 kg
• Casing: low-flammable polypropylene
• Bearings: ball, 40,000 hours
• Ingress protection: IPX4

Frequently asked questions

Is the 250 louder than the 200?
No, slightly quieter if anything: 44 to 51 dB(A) against 45 to 52, both at three metres. A larger impeller moves the same air at lower velocity.

What does it draw?
125 watts on low and 177 on high.

How should I hang it?
From two points that carry the weight, preferably loose in straps or rope hangers so vibration does not travel into the structure.

Can it be mounted upright?
Yes, any orientation. The ball bearings allow any mounting direction.