1. Introduction
The AIRSTAGE VR-II indoor unit range represents Fujitsu General’s second-generation VRF indoor platform, developed for use with the VR-II Heat Recovery System. No.2_Indoor_unit_EN_20120118 No.4_Compativility_EN_20120118
The lineup maintains compatibility with many existing indoor unit types from the V-II series while introducing electrical, control, and service improvements to enhance reliability and installation simplicity
2. Product Lineup Overview
A. Range
12 types / 55 models, covering 2.2 kW to 25.0 kW, identical in capacity range to the V-II series.
Designed to accommodate diverse architectural applications — from commercial spaces to hospitality and residential environments.
B. Indoor Unit Types
| Category | Typical Model Series | Key Applications |
|---|---|---|
| Compact Cassette / Standard Cassette | AUXB / ARXB Series | Offices, meeting rooms, retail zones |
| Compact Duct / Slim Duct / Low Static Duct | ARXD / ARXA Series | Hotels, residential, and partitioned spaces |
| High Static Pressure Duct | ARXC / AB*A Series | Large offices, open commercial layouts |
| Floor / Ceiling | ABA / ASA Series | Shops, classrooms, or areas with limited ceiling space |
| Compact Wall Mounted / Wall Mounted | ASA / ASE Series | Smaller rooms or spaces needing quick installation |
All indoor models maintain consistent airflow performance, compact dimensions, and simplified service access compared to the previous generation.
3. Technical Enhancements
A. Remote Controller Wiring — Non-Polar 2-Wire System
Transitioned from the polar 3-wire system used in V-II to a non-polar 2-wire communication method for remote controllers.
Benefits:
Easier wiring and reduced installation error risk.
Supports new-generation wired remotes (UTY-RNR, UTY-RNH, UTY-RSK, UTY-RHK).
Important: Mixed installation between polar and non-polar systems is not permitted
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B. External Output Specification Changes
Control signal output redesigned for DC12–24V range, allowing broader integration with external control devices and building management systems (BMS).
Enhanced relay coil voltage handling and contact resistance tolerance improve field flexibility.
For systems equipped with DC24V power supply, a DC/DC relay is recommended (field supplied) for safe interface operation.
C. “EEV Connection Error” Function Added
A new diagnostic circuit detects Electronic Expansion Valve (EEV) connection faults between indoor and outdoor units.
When a fault occurs:
The system immediately halts outdoor unit operation.
Protects compressor components and prevents refrigerant circulation damage.
Enhances system reliability and reduces downtime
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4. Optional Parts and Accessories
Most optional parts are shared with the V-II and J-II indoor units, allowing dealers and service providers to maintain common inventories.
Key options by type include:
| Indoor Unit | Optional Accessories |
|---|---|
| Cassette / Compact Cassette | Decoration Panels (UTG-UFC-W / UTG-UGA-W), Fresh Air Intake Kit (UTZ-VXAA / VXGA), Shutter Plate (UTR-YDZB), Humidity Insulation Kit (UTZ-KXGB / KXGC) |
| Slim & Compact Duct | Auto Louver Grille Kit (UTD-GXSA/B/C), IR Receiver (UTB-YWC / TWC), Long-Life Filter (UTD-LF25NA), Drain Pump Unit (UTZ-PX1BBA) |
| Low / High Static Duct | Remote Sensor (UTD-RS100), Flange (UTD-RF204 / SF045T), Long-Life Filter (UTD-LF60KA) |
| Wall Mounted | EV Kits (UTR-EV09XB / EV14XB), IR Receiver Unit (UTB-YWC / TWC) |
| Ceiling / Floor | Drain Pump Unit (UTR-DPB24T), Motion Sensor Input compatibility |
5. Auto Louver and Comfort Function
For Slim Duct units:
Optional Auto Louver Grille Kit enables horizontal airflow adjustment synchronized with the wired or wireless remote controller.
The result is improved temperature distribution during both heating and cooling cycles, ensuring even comfort across the room
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6. Compatibility Overview
The VR-II system retains broad compatibility across multiple product generations, minimizing disruption for existing customers or ongoing projects:
| Compatibility Category | VR-II | V-II | J-II | Notes |
|---|---|---|---|---|
| Central Controllers | ✅ Compatible | ✅ Compatible | ✅ Compatible | System Controller (UTY-APGX) & Energy Manager (UTY-PEGX) from Ver. 0.2.3.0 onward |
| Remote Controllers | ✅ Compatible | ⚠️ Partial | ⚠️ Partial | Older controllers functional but limited in features |
| Network Converters (LONWORKS / BACnet) | ✅ Supported | ✅ Supported | ✅ Supported | Integration-ready with BMS via UTY-VLGX and UTY-ABGX |
| Service Tools | ✅ Supported | ✅ Supported | ✅ Supported | UTY-ASGX and Web Monitoring Tool (UTY-AMGX) remain usable |
| RB Units / Separation Tubes / Headers | ✅ New Components | ❌ Not available | ❌ Not available | New hardware introduced specifically for VR-II Heat Recovery Systems No.4_Compativility_EN_20120118 |
7. Training Key Points
For installation and service teams, the following points should be reinforced:
Do not mix controller wiring standards (3-wire vs. 2-wire).
Confirm relay voltage compatibility when integrating with DC24V control systems.
Check for EEV connection error codes during commissioning — they are a new diagnostic indicator.
Utilize UTY-ASGX Service Tool for rapid fault isolation and operational monitoring.
Leverage existing accessories from V-II/J-II where applicable to reduce installation cost.
8. Summary for Sales and Technical Staff
The VR-II Indoor Unit lineup builds on Fujitsu’s long-standing reliability while incorporating several innovations focused on:
Simplified installation,
Improved system protection,
Enhanced interoperability, and
Expanded optional accessory support.
It ensures seamless integration into modern building environments while retaining the trusted durability of earlier AIRSTAGE systems.