Motorized KNX Valve Actuator (VD21A01KNX) is an Eelectron product for KNX-based building automation. The VD21A01KNX is an Eelectron KNX motorized actuator for controlling heating or cooling valves. It mounts directly onto compatible valve inserts using an M30 × 1.5 threaded connection. The actuator includes an integrated temperature sensor and supports room-temperature control, allowing it to participate in KNX-based heating and cooling regulation. A mechanical position indicator provides a visible indication of valve travel, while automatic stroke detection helps the actuator adapt to the connected valve. The device also includes a configurable input that can be used as a binary input or for a compatible remote sensor arrangement.

Technical data specifies a valve stroke of 1.0–4.2 mm, positioning force of 80–120 N, maximum noise emission of 28 dB(A), dimensions of 76 × 47 × 85 mm and maximum KNX current consumption of 20 mA. It includes an integrated KNX bus coupling unit and a valve-protection function, and can be used on heating-circuit distributors. Eelectron identifies Heimeier valve inserts as the basic compatible configuration; other manufacturers’ valve inserts may require a suitable adapter, and correct operation is not guaranteed for every combination. The manufacturer currently marks this product as discontinued, which should be considered when specifying replacements or new installations.