The Aumüller KS2 and KS4 chain drives are slim drives for bottom-hung and top-hung windows, for ventilation and smoke extraction. If one is faulty, Vent Systems has a replacement with the same force – selected by force, stroke and voltage.
Aumüller KS2 / KS4 and Vent Systems alternative compared
| Feature | Aumüller KS2 | Aumüller KS4 | Alternative from Vent Systems |
|---|---|---|---|
| Voltage | 24 V DC, also 230 V | 24 V DC | VS-KA: 24 V or 230 V · VS-KA-i: 24 V |
| pulling force | 250 N | 400 N (push force lower depending on stroke) | VS-KA: 250 or 400 N · VS-KA-i: 250 or 500 N |
| Stroke | incl. 500 and 800 mm | 50–1000 mm, programmable | VS-KA: 100–450 mm · VS-KA-i: 300–1400 mm |
| Cross-section | slim, KS4: 35 × 24 mm | VS-KA is larger – check the space on the frame | |
| Degree of protection | IP32 | IP32 | VS-KA: IP32 |
| Application | Ventilation, SHEV, NSHEV | Ventilation and SHEV (not as part of a tested NSHEV) | |
Which drive fits?
- KS2 with stroke up to 450 mm: VS-KA with 250 N, in 24 V or 230 V. Bracket set included in the price.
- KS4 with stroke up to 450 mm: VS-KA with 400 N in 24 V.
- Stroke over 450 mm: VS-KA-i smart chain drive (24 V) with 250 or 500 N and stroke up to 1400 mm, also several drives synchronised.
What to consider when replacing a drive
- Installation space: KS2 and KS4 are very slim. Measure the space on the window frame before you order.
- Stroke: You will usually find the programmed stroke of the old drive on the type plate. Choose the same or a smaller stroke.
- Voltage and control: Choose the same voltage as before. 24 V drives run on a ventilation or SHEV control unit.
Important for SHEV: If the window is part of a tested natural smoke and heat exhaust ventilator (NSHEV), the drive may only be replaced by a type named in the test or declaration of performance of the NSHEV. If in doubt, ask your SHEV specialist or us.
Photograph the type plate – we will name the right drive
Send us a photo of the type plate and the window via WhatsApp to +49 176 57801935 or call us: +49 40 50694631 (Mon–Fri 8 am–5 pm). You will receive a specific recommendation with price – stock items shipped from Hamburg within 24 hours.
All Aumüller drives at a glance: Replacing Aumüller window drives. All manufacturers in one list: replacement table for window drives (PDF)
Aumüller, KS2 and KS4 are trademarks or product names of AUMÜLLER AUMATIC GmbH. Vent Systems is not affiliated with Aumüller. The manufacturer data comes from publicly available product information (as of October 2026) and is for technical comparison only. Please check dimensions and values on the existing drive before replacing it.
Frequently asked questions
Which actuator replaces the Aumüller KS2?
For strokes up to 450 mm, the VS-KA with 250 N in 24 V or 230 V fits as an alternative from Vent Systems. The bracket set is included in the price.
Which actuator replaces the Aumüller KS4?
Up to a 450 mm stroke, the VS-KA with 400 N in 24 V fits. For longer strokes up to 1400 mm, the smart VS-KA-i with 250 or 500 N is suitable.
Is the replacement also suitable for smoke ventilation?
The VS-KA is suitable for ventilation and smoke ventilation, but not as part of a tested smoke exhaust device (NSHEV). For smoke ventilation, agree the replacement with the installer.
Note: The brand and product names mentioned belong to their respective owners. They are used here only to indicate technical compatibility. Vent Systems is not affiliated with these manufacturers; only Vent Systems’ own actuators are offered.
In brief: As an alternative to the Aumüller KS2 and KS4 chain actuators, Vent Systems offers the VS-KA with 250 or 400 N for strokes up to 450 mm, in 24 V or 230 V. For longer strokes up to 1400 mm, the smart VS-KA-i with 250 or 500 N fits. Because the KS2 and KS4 are very slim, measure the space on the frame beforehand.