Overview
The AIRSTAGE S-Series was one of Fujitsu General’s pioneering Variable Refrigerant Flow (VRF) systems. Introduced in the early 2000s, the S-Series was designed for small-to-medium commercial buildings, offices, and multi-zone applications requiring precise temperature control, quiet operation, and dependable performance.
Operating on R407C refrigerant, the S-Series established Fujitsu General’s reputation for high-quality, energy-efficient VRF systems that continue to perform reliably in the field decades later.
Key Features
1. Variable Refrigerant Flow (VRF) Control
The S-Series uses inverter-driven compressors to precisely match capacity to the actual cooling or heating demand of connected indoor units. This provides stable comfort conditions while reducing energy consumption compared to traditional fixed-speed systems.
2. Multi-Zone Capability
Up to 16 indoor units can be connected to a single outdoor unit (model dependent), allowing individual control of temperature in different rooms or zones. This makes it ideal for offices, hotels, schools, and mixed-use buildings.
3. Compact and Quiet Operation
Engineered with a slim outdoor profile and low sound levels, the S-Series can be installed in tight spaces or on rooftops without disrupting the surrounding environment.
4. Reliable R407C Refrigerant
Using R407C, a blended HFC refrigerant, the S-Series provides solid efficiency and capacity retention while remaining compliant with early international environmental standards. It was an important transitional step between legacy R22 systems and today’s modern R410A/R32 VRF technology.
5. Extended Piping Flexibility
The system’s robust piping design supports long runs and multiple branch connections, making it suitable for both new installations and retrofit projects.
Technical Highlights
| Feature | Specification (Typical) |
|---|---|
| Refrigerant | R407C (Zeotropic blend) |
| Compressor Type | DC inverter-driven scroll or rotary |
| Connectable Indoor Units | Up to 16 (model dependent) |
| Mode | Cooling / Heating (Heat Pump) |
| Application Range | Small to medium commercial buildings |
| Control System | Wired and centralized controller compatibility |
| Typical Operating Period | 2001–2010 (approximate) |
Service & Maintenance Notes
Charging Method: Always charge with liquid refrigerant by weight to maintain blend integrity.
Refrigerant Glide: R407C has a temperature glide; service personnel must monitor subcooling and superheat accurately during maintenance.
Spare Parts: Although production has ceased, major components such as PCB boards, sensors, and expansion valves remain available through Fujitsu General’s authorized service network.
Upgrade Planning: Customers with legacy S-Series installations are encouraged to explore modern AIRSTAGE J-III or VR-II systems for improved energy efficiency, R32 compatibility, and advanced control integration.