RACA Journal I February 2026 www. refrigerationandaircon. co. za 21
VRF
Toshiba is also a pioneer in introducing NFC communication between the outdoor unit and the technician, allowing instant setup, commissioning and diagnostics via a smartphone, significantly reducing on-site time and service costs,” says Massyn.
He notes that common maintenance issues in multi-zone VRF installations include incorrect refrigerant charging, poor piping practices, misconfigured controls, all of which can lead to reduced capacity or system instability.“ Toshiba address this with best-in-class VRF design and selection software that minimises installation errors, plus a structured‘ train-the-trainer’ approach, ensuring local partners, distributors and contractors gain deep technical capability that cascades effectively across their service team.”
The shift to A2L refrigerants has strengthened standard maintenance protocols by adding stricter leak-prevention practices, airflow verification, room size checks and more careful recovery / charging procedures due to mild flammability. Massyn explains that technicians are now expected to follow enhanced safety routines such as using A2L-rated leak detectors, verifying charge limits per room size.“ Additional skills include A2L-specific brazing and evacuation practices, familiarity with revised F-gas / ISO standards and competency in handling systems equipped with integrated leak-detection and safety-shutoff features.”
Modern VRF systems increasingly support automated maintenance features such as embedded fault-detection diagnostics, real-time sensor analytics, refrigerant-leak monitoring and predictive service-intervals through cloud.“ These functions allow the system to identify abnormal pressures, temperatures or compressor behaviour early and notify technicians before performance is impacted. By preventing major failures, optimising running conditions and reducing downtime, system longevity is improved and user trust is strengthened. Customers see quieter operation, fewer unexpected breakdowns and faster / more accurate service interventions,” advises Massyn.
THE FUTURE OF FLEXIBLE, EFFICIENT AND SAFE HVAC
Recent discussions on ASHRAE Journal podcasts numbers 29 and 52 highlighted how VRF technology has advanced over the years, responding to changing refrigerants, international trends and evolving safety standards. The conversations offered a rare inside look at the challenges and opportunities that shape this sector, from simultaneous heating and cooling to the meticulous work behind ASHRAE Standard 15.
At the heart of VRF’ s appeal is its flexibility. Unlike traditional HVAC systems, which often require separate units for heating and cooling in each zone, VRF systems use a single refrigerant circuit to serve multiple zones, adjusting output based on demand. One of the technology’ s standout features is its heat recovery capability, which allows simultaneous cooling in one area and heating in another. Scott McGinnis, P. E., a veteran engineer and ASHRAE committee participant, emphasised that this feature is particularly valuable for buildings with varied occupancy patterns or fluctuating thermal loads.“ You can transfer energy from spaces that need cooling to spaces that need heating, improving efficiency and lowering operating costs,” he noted. Despite being commercially available for decades, VRF systems have historically been accompanied by a range of terminology that can confuse newcomers. Different manufacturers have referred to the central component that manages heat recovery – the‘ heat recovery control unit’ – under brand-specific names like mode selector box, flow selector, changeover box or switch box. ASHRAE has worked to standardise this terminology in the VRF guideline SGPC 41 and the Handbook, providing a common reference point for engineers, contractors and building owners. Standardised terminology, the presenters agreed, is crucial for ensuring consistent understanding and safe application across projects.
The evolution of VRF is inseparable from changes in refrigerant technology. In North America, the industry has transitioned from high-global warming potential( GWP) substances like R410A to mildly flammable, low-GWP A2L refrigerants such as R32. These refrigerants represent a significant step forward in environmental responsibility, but their introduction required extensive updates to safety standards. Panellist Christopher William, an ASHRAE Standard 15 contributor, explained that while A2L refrigerants are flammable, they are characterised by low burning velocity and slow flame spread, making them far safer than many initially thought. Laboratory research even demonstrated that, under controlled ignition conditions, these refrigerants absorb heat and resist rapid combustion – in one experiment, a refrigerant flow repeatedly extinguished candles on a test bench before ignition could occur.
The safety of these refrigerants is codified in ASHRAE Standard 15, the century-old guideline for refrigerant handling and system design in buildings. Originally focused on more conventional systems, the standard has undergone major revisions to accommodate VRF technology and A2L refrigerants. Over a two-year period, Standard 15 expanded from 18 pages to more than 80, detailing requirements for leak management, fire safety and system operation. The work has been painstaking and collaborative, involving consensus-driven discussions across committees, subcommittees and public review processes. Each proposed change undergoes rigorous debate, review and testing to ensure applicability, defendability and safety in real-world scenarios. It all takes time.
One practical outcome of these updates is the integration of advanced leak detection and safety mechanisms in VRF systems. Modern fan coil units now feature refrigerant leak detectors and upstream shutoff valves. In the event of a leak, these devices can isolate small amounts of refrigerant, preventing large-scale losses and facilitating faster maintenance. Historically, engineers had to design systems assuming worst-case leaks of up to 60kg of refrigerant in a single space, primarily to prevent oxygen deprivation. With these new safety features, leaks are more easily managed and limited, enhancing system reliability and operator confidence. Looking ahead, the VRF landscape is expected to remain stable and reliable, with incremental improvements in refrigerant technology and safety standards continuing to enhance performance. While Europe experiments with CO₂ and propane systems, North America is likely to remain committed to A2L refrigerants such as R32 for the foreseeable future. This provides manufacturers, engineers and building owners with a predictable foundation for design and operation. feature
RACA Journal I February 2026 www. refrigerationandaircon. co. za 21