RACA Journal I June 2026 www. refrigerationandaircon. co. za 3
TECH TALK
GENERAL AIR SOLUTIONS, ACTUATORS FOR RELIABLE AIR CONTROL
By Eamonn Ryan
This article summarises key insights from a technical presentation to the SAIRAC Cape Town Centre in February 2026 by Johan van der Vyver, general manager: Belimo South Africa. networking associations
At the heart of modern HVAC systems is precise control of airflow and water flow. Central to this are actuator technologies and advanced valves, which regulate dampers and hydronic circuits to optimise comfort and system efficiency. Belimo’ s comprehensive air solutions portfolio includes rotary, linear and full‐rotation actuators engineered to motorise air control dampers and slide valves across a broad range of applications.
ACTUATORS: FOUNDATION OF AIR CONTROL Belimo actuators are the core of damper volume control in HVAC systems. Their product range covers:
• Standard rotary actuators for general damper control.
• Linear actuators for valve and slide applications.
• Form‐fit designs for secure mechanical connections.
• Models with varying torque outputs( from small to heavy duty) suitable for everything from residential dampers to large industrial systems.
• Environmental ratings such as IP66 for operation in harsh or outdoor environments.
Many commonly used actuator types are available with higher protection ratings for demanding conditions, though not across the entire range.
A key safety feature in these actuators is the fail‐safe mechanism, available in two main forms:
• Spring return actuators: internal springs automatically drive dampers to a pre‐defined safe position( fully open or closed) during power loss – critical for applications such as fire and smoke control.
• Capacitor‐based( supercap) actuators: store electrical energy to reposition the actuator during power failure. Unlike traditional spring return units, supercap actuators can move to specific fail‐safe positions( for example, 10 % and 50 %) rather than just fully open or closed, providing more nuanced control for safety or HVAC sequences.
NEW DIGITAL GENERATION IS THE FUTURE OF SMART HVAC Belimo is progressing towards digitised field devices with its New Digital Generation( NDG) platform, a step change in HVAC control technology. This evolution aims to make devices smarter, easier to install, and simpler to commission and manage over their lifecycle.
A flagship innovation is the Belimo Assistant 2 mobile app, which uses NFC( near‐field communication). Crucially, this enables configuration and device‐setting adjustments even when a device is unpowered – removing traditional barriers to on‐site commissioning and troubleshooting.
At the core of this platform is Belimo’ s proprietary M600 microchip, which delivers refined control, improved operational efficiency and quieter operation compared to legacy electronics. The custom chip strategy reduces dependency on external suppliers and strengthens Belimo’ s ability to tailor device behaviour precisely.
Practical enhancements include:
• LED status displays on devices for instant visual feedback during setup and troubleshooting.
• Tool‐free electrical interfaces, such as lever systems, that simplify wiring and reduce potential installation errors.
Overall, the NDG platform reflects the broader industry trend toward connectivity, intuitive diagnostics and enhanced performance in smart building systems.
Supplied by Belimo
Regardless of mechanism, these fail‐safe actions are single‐action safety functions: once triggered by power loss, the actuator must be reset before normal operation resumes.
The TechTalk in Cape Town.
RACA Journal I June 2026 www. refrigerationandaircon. co. za 3