AC Infinity CLOUDLINE Pro T4

A 100 mm inline fan, 205 CFM (348 m³/h) at 28 dBA, supplied with the Controller 69 Pro and a climate probe. Controls on temperature, humidity and VPD.

The CLOUDLINE Pro T4 is the same fan as the S4, but with a smart controller instead of a speed dial. That brings with it one setting many growers overlook, and it does exactly what they are after.

Off is not off, it is a floor

The level you set in OFF mode is not the fan's on/off switch. It is the level it runs at whenever another mode switches it off. Put speed two there and the fan keeps running at speed two continuously, only rising when your temperature or humidity threshold is crossed.

That is nearly always what you want. A fan that genuinely stops leaves the air in the tent standing, and humidity around the leaves then climbs without your meter up top showing it. A low baseline speed keeps the air moving and keeps your carbon filter doing its job.

If you do want the fan to stop completely, set that OFF value to zero. It is the only way it truly switches off, and it answers the most common question about this controller: if it will not switch off when your programme says it should, the OFF level is not at zero.

The same logic applies at the other end. The ON value is the ceiling: the level it rises to once a trigger fires. Do not set that one to zero, or the fan will do nothing at the moment it is supposed to act.

Programming a day: which mode for what

Besides AUTO the controller has three more ways to drive the fan, and they do not do the same job. It pays to know which is for what.

AUTO drives on what the probe reads, with four thresholds: a high and a low for temperature and the same two for humidity. All four can be active at once. If you use only one, switch the others off, because a forgotten low trigger is the most common reason a fan starts at an unexpected moment.

TIMER TO ON and TIMER TO OFF are one-shot countdowns. Useful when airing a room out or after spraying, not meant for your daily control.

CYCLE runs the fan on and off for set durations regardless of what the probe reads. That is the mode for a space you want refreshed periodically without a reading having to be crossed.

SCHEDULE works on the clock: on at seven in the morning, off at seven in the evening, the same every day. Set the clock under the settings first. An internal battery keeps it running, so your schedule survives a power cut.

In practice you combine two: AUTO for the response to your climate, with an OFF value as baseline ventilation. Leaving a mode pauses that mode's programme, so leave the controller on the one you actually want running.

S4 or T4

The fan is identical either way, so the price difference is the controller and its probe. If you are unsure, the question is simple: do you want extraction that reacts to heat or humidity on its own, or will you set a speed by hand and leave it there?

Technical Specifications:

• Model: AI-CLT4
• Duct size: 100 mm (4 inch)
• Airflow: 205 CFM (348 m³/h)
• Noise: 28 dBA
• Static pressure: 223 Pa
• Power draw: 28 W maximum, 21 W average
• Controller: Controller 69 Pro, four ports, probe included
• Drives on: temperature, humidity, VPD, timer, cycle and schedule
• Connectivity: Wi-Fi on 2.4 GHz and Bluetooth
• Motor: brushless EC motor with PWM control
• Bearings: dual ball, 67,000 hours
• Ingress protection: IP44
• Fan dimensions: 17.6 x 30.3 x 18.8 cm

Frequently asked questions

Why does my fan never switch off?
Because the OFF level sits above zero. Set it to zero if you want it to stop.

What is the difference from the S4?
The fan is identical. The T4 adds the Controller 69 Pro and the climate probe, the S4 comes with a wired ten-speed controller.

Can I add more devices to it?
Yes, up to four on the controller and more with a splitter. They do need to be AC Infinity UIS devices.

Does my programme keep running without internet?
Yes. The controller stores its own settings; the connection is for remote control and insight.

Do I have to reset the clock after a power cut?
No, an internal battery keeps the time. Your schedule carries on.

Can I run two modes at once?
The controller runs whichever mode it is in. Leaving that mode pauses its programme until you return, so leave it on the one you want.