Description
Dependable AC Extraction in an Airtight Steel Duct Fan
The Systemair K AC is the AC-motor version of Systemair's K circular duct fan, sold in the UK by G.A.S. (Global Air Supplies) as the K Fan AC. It pairs a backward-curved radial impeller with an external-rotor AC motor inside a sealed galvanised steel casing, so stale, odour-laden air stays in the duct and goes out through the carbon filter instead of seeping from the fan body. The XL and L models put a bigger motor into the same duct size for more airflow, and every model is speed-controllable with an ordinary AC fan controller — a simple, hard-wearing choice for grow tent and grow room extraction.
Key Benefits
- Sealed, airtight casing — galvanised steel, air-tightness class C to EN 1751, so odours cannot leak from the fan body
- 180 to 1,340 m³/h across the range, from the 4" (100mm) M to the 12" (315mm) M, with the XL models moving 285 m³/h on 4", 359 m³/h on 5" and 724 m³/h on 6" duct, and the L models 965 m³/h on 8" and 979 m³/h on 10"
- Speed control with a triac or voltage (stepless) controller or a 5-step regulator
- Built-in motor protection against overheating
- Suits humid rooms — IP55 terminal box and a casing approved for indoor or outdoor installation
- Mounts in any position with the supplied bracket and 25mm spigots made for fast clamps
- Maintenance-free, with a 2-year warranty
Is Your Tent Too Hot, Too Humid or Leaking Odour?
Lights add heat and plants add moisture, so a grow tent without steady extraction soon runs hot and humid — conditions that slow growth and invite mould and mildew. Good extraction also holds the tent at a slight negative pressure, so fresh air is drawn in through the vents and everything leaving goes out through the carbon filter for proper odour control. The K AC's airtight body means the air you are pulling through the filter does not escape from the fan casing on the way, and pairing it with a thermostatic speed controller lets it run slower and quieter when the tent is cool and faster as the temperature and humidity climb, keeping airflow matched to what the space needs.
How to Use
- Size it to your space: multiply length × width × height in metres, then × 60 for one complete air change a minute, and add 25–50% for the carbon filter and ducting. A 1.2 × 1.2 × 2 m tent comes out at about 215–260 m³/h, which the 4" (100mm) XL covers at 285 m³/h.
- Mount it: fix the bracket inside or outside the tent; the fan runs in any orientation, with the airflow arrow on the label pointing away from the carbon filter.
- Connect the ducting: push the ducting or carbon filter onto the 25mm spigots and secure each joint with a fast clamp.
- Power it: the fan is pre-wired with an IEC connector — use a UK kettle lead (IEC C13), sold separately, straight to the mains or through a fan speed controller.
- Control it: set the speed with a triac or voltage AC controller, or use a thermostatic model so the fan follows the tent temperature.
Technical Specifications
- Duct size: 100mm, 125mm, 150mm, 200mm, 250mm or 315mm
- Airflow: 180–1,340 m³/h
- Brand: Systemair (sold in the UK by G.A.S. as the K Fan AC)
- Type: AC circular inline duct fan with backward-curved radial impeller
- Airflow, 4" (100mm) M: 180 m³/h maximum
- Airflow, 4" (100mm) XL: 285 m³/h maximum
- Airflow, 5" (125mm) M: 187 m³/h maximum
- Airflow, 5" (125mm) XL: 359 m³/h maximum
- Airflow, 6" (150mm) M: 464 m³/h maximum
- Airflow, 6" (150mm) XL: 724 m³/h maximum
- Airflow, 8" (200mm) M: 760 m³/h maximum
- Airflow, 8" (200mm) L: 965 m³/h maximum
- Airflow, 10" (250mm) M: 788 m³/h maximum
- Airflow, 10" (250mm) L: 979 m³/h maximum
- Airflow, 12" (315mm) M: 1,340 m³/h maximum
- Motor: AC external-rotor motor
- Supply: 230 V single phase, 50/60 Hz
- Speed control: triac or voltage (stepless) controller, or 5-step regulator
- Motor protection: integrated thermal protection with manual reset; impedance-protected motor on the 4" (100mm) and 5" (125mm)
- Enclosure: IP44 motor, IP55 terminal box
- Casing: galvanised sheet steel, corrosion class C3, air-tightness class C (EN 1751)
- Impeller: backward-curved, glass-fibre-reinforced polyamide, dynamically balanced
- Power connection: IEC connector; UK mains lead not included
- Installation: any position, indoors or outdoors; mounting bracket included; 25mm spigots for fast clamps
- Warranty: 2 years
Frequently Asked Questions
What do the M, XL and L letters mean?
They are Systemair's output classes for a given duct size. The XL (on 4", 5" and 6" duct) carries a larger motor and impeller than the standard M, and the L (on 8" and 10" duct) a more powerful motor, so both move more air through the same ducting.
Can I control its speed?
Yes. It works with the triac and voltage (stepless) controllers made for AC fans, or a 5-step regulator. A thermostatic controller will raise and lower the speed with the tent temperature.
Does it come with a plug?
It is pre-wired with an IEC connector rather than a UK plug, so you need a UK kettle lead (IEC C13) to power it, sold separately.
Should I choose the AC or the EC version?
Systemair also build the K with an EC motor (the K EC), which uses less electricity and is controlled by a 0–10 V EC controller. The AC version costs less to buy and runs on the simple AC speed controllers many growers already own.
Can it run in a humid grow room?
Yes. G.A.S. rate the K AC as suitable for ventilating humid rooms, the terminal box is IP55, and Systemair approve the K for indoor or outdoor installation.
Works Well With
