GENERAL AIRSTAGE PRODUCT REFERENCE AIRSTAGE J Series – 6HP Compact R410A VRF System | 15.2 kW Class System overview, model compatibility, controls, piping, installation, optional parts and fault reference | | Legacy product notice: This reference relates to the original AIRSTAGE J Series 6HP R410A platform. Confirm the full indoor and outdoor model number, model-change code and applicable manual before ordering parts, changing settings or commencing repairs. |
| Quick navigation Quick Summary Outdoor Units Indoor Units Controls Piping Installation Optional Parts Fault Reference Technician Checks | 1. Quick summary | | Item | Detail | | Product type | Compact variable refrigerant flow system | | Nominal outdoor capacity | 15.2 kW cooling class | | Refrigerant | R410A | | Power supply | Single-phase, 220–240 V, 50 Hz | | Connectable indoor units | 1 to 8 indoor units | | Indoor-unit connection ratio | 50% to 150% of outdoor-unit nominal capacity; total rated indoor capacity 7.6 to 22.8 kW | | Maximum actual pipe length | 70 m from outdoor unit to farthest indoor unit | | Maximum total pipe length | 115 m | | Maximum height difference | 30 m between outdoor and indoor units | | Operating range | Cooling: -5°C to 43°C; heating: -20°C to 21°C for heat-pump models |
| 2. Outdoor units | | Function | Fujitsu model family | GENERAL model family | | Heat pump / reverse cycle | AO*54UJBMR | AJ*A54LCLR | | Cooling only | AO*54FJBMR | AJ*A54JCLR |
| Key outdoor specifications | | Specification | Value | | Rated cooling capacity | 15.2 kW | | Rated heating capacity | 16.6 kW on heat-pump models | | Rated input | Cooling 4.75 kW; heating 4.88 kW | | COP | Cooling 3.20; heating 3.40 | | Compressor | DC inverter scroll compressor, 3,000 W motor output | | Factory refrigerant charge | 3.0 kg R410A | | Outdoor dimensions | 900 × 900 × 370 mm; approximately 979 mm wide including valve cover | | Net weight | 97 kg | | Sound pressure | 56 dB(A) normal; 51 dB(A) silent mode | | Outdoor pipe connections | Liquid 9.52 mm; gas 19.05 mm; flare connection |
| 3. Compatible indoor-unit families | | Indoor type | Typical model codes | Capacity range / notes | | Compact duct | AR7, AR9, AR12, AR14, AR18, AR22 | Ultra-thin universal installation; rear or bottom return-air arrangement | | Low-static duct | ARXB25, ARXB30 | Designed for narrow ceiling spaces; recommended static pressure 0–80 Pa | | Standard duct | AR25, AR30, AR36, AR45 | Flexible ducted installation; up to 180 Pa on applicable models | | Compact cassette | AU7, AU9, AU12, AU14, AU18 | Fits 600 × 600 mm ceiling grid; selectable 2-, 3- or 4-way airflow | | Cassette | AU20, AU25, AU30, AU36, AU45, AU54 | 4-way cassette with adjustable installation height and long-life filter | | Compact wall mounted | AS7, AS9, AS12, AS14 | Compact wall unit with washable panel and auto-swing louvre | | Wall mounted | AS18, AS24, AS30 | Larger-capacity wall-mounted indoor units |
| | Capacity note: A system can accept indoor units with a combined rated capacity up to 150% of the outdoor rating, but the actual capacity available to each indoor unit may be reduced when the combined operating demand exceeds the outdoor unit's available capacity. |
| 4. Controls and communication | | Controller type | Models / application | | Wireless remote controller | Accessory for indoor units; supports ON, OFF, program and sleep timers and can be used for system addressing during installation. | | Wired remote controller | UTB-YUB / UTB-GUB / UTB-TUB families; weekly timer, setback and room-temperature sensing functions. | | Simple remote controller | UTB-YRA / UTB-GRA / UTB-TRA and UTB-YPB / UTB-GPB / UTB-TPB families. | | Group remote controller | UTB-YDB / UTB-GDB for centralised control of the connected indoor units. | | IR receiver unit | Used with duct indoor units to receive wireless remote-controller commands; model families UTB-YPB, UTB-GPB and UTB-TPB. | | Remote-controller quantity | Up to two remote controllers can be connected to one indoor unit where supported. | | System wiring | Combined power-source and signal wiring between equipment: three conductors plus earth, subject to the applicable wiring diagram and local rules. |
| 5. Refrigerant piping design | | Limit | Requirement | | Shortest permitted system pipe length | 7.5 m | | Outdoor to farthest indoor unit | 70 m maximum actual length | | Total system pipe length | 115 m maximum | | Outdoor to first branch kit | 60 m maximum | | First branch to farthest indoor unit | 40 m maximum | | EV kit to indoor unit | Generally 1.2 m maximum under the system limitation table; also confirm the indoor-unit and EV-kit installation instructions. | | Outdoor-to-indoor height difference | 30 m maximum | | Indoor-to-indoor height difference | 15 m for AJ*A54 family; 5 m for AO*54 family |
| Pipe sizes | | Location / indoor model code | Liquid pipe | Gas pipe | | Outdoor-unit connection | 9.52 mm | 19.05 mm | | Indoor codes 7 and 9 | 6.35 mm | 9.52 mm | | Indoor codes 12 and 14 | 6.35 mm | 12.70 mm | | Indoor codes 18, 20, 22, 24 and 25 | 6.35 mm | 15.88 mm | | Indoor code 30 | 9.52 mm | 15.88 mm | | Indoor codes 36, 45 and 54 | 9.52 mm | 19.05 mm |
| | Piping restriction: A separation tube must not be installed downstream of a header. Maintain at least 0.5 m of straight pipe before and between applicable branch fittings, orient separation tubes within the permitted angle, and use nitrogen while brazing. |
| 6. Critical installation requirements | | Area | Requirement | | Outdoor clearances | Use the model-specific clearance diagrams. Restricted airflow or recirculation can reduce capacity and cause high-pressure faults. | | Outdoor mounting | Install on a strong, level stand; do not install directly on the ground; protect from strong wind and excessive dust. | | Branch-kit orientation | Install separation tubes horizontally within ±15° or vertically in an approved orientation so refrigerant divides evenly. | | Brazing | Flow dry nitrogen through refrigerant piping during brazing to prevent internal oxide scale. | | Insulation | Fully and separately insulate liquid and gas pipes and seal all joints. Inadequate insulation can cause condensation, water damage and capacity loss. | | Additional charge | Calculate from total liquid-pipe length: 9.52 mm pipe × 0.06 kg/m plus 6.35 mm pipe × 0.02 kg/m, using the complete manual procedure. | | Pipe-length switch | Set outdoor PCB pipe-length DIP switches for the actual distance to the farthest indoor unit. Incorrect settings can result in insufficient capacity or abnormal pressure. | | Circuit protection | Confirm breaker capacity and outdoor DIP-switch settings. The manual notes that operation with a breaker below 30 A requires specific settings and may reduce performance. | | Addressing | System addressing can be completed with the wireless remote controller; verify all refrigerant-system and indoor-unit addresses before test operation. |
| 7. Optional parts | | Part | Model / description | | Separation tube | UTR-BP054X / UTR-BP54U and UTP-AX054A families; supplied with gas and liquid branches and insulation components. | | Branch header | UTR-HD546U, including gas and liquid header assemblies, closed pipes, insulation and binders. | | EV kit – 6.35 mm liquid | UTR-EV2AL; approximately 83 × 288 × 45 mm. | | EV kit – 9.52 mm liquid | UTR-EV3L; approximately 97 × 290 × 50 mm. | | Duct accessories | Remote sensor UTD-RS100; square flange UTD-SF045T; round flange UTD-RF204; long-life filter UTD-LF270; model-specific drain-pump kits. | | Controllers | Wired, simple and group remote controllers and IR receiver units listed in the control-system chapter. |
| 8. Fault and operating-display reference | | Outdoor PCB display: LED 1 identifies the display mode and LEDs 2–6 provide operation or fault detail. Normal displays include cooling, heating, compressor-frequency bands, pressure balance, oil recovery, defrost, test run, pump-down completion, solenoid-valve operation and compressor-speed protection. |
| Outdoor abnormal-mode categories | | Category | Faults represented in the manual | | Power and PCB | Power-source frequency abnormal, EEPROM error and microcomputer communication error. | | Communication | Network communication error and indoor-unit error indication. | | Pressure and temperature | Discharge-temperature error, high-pressure error, low-pressure error and pump-down errors. | | Sensors | Discharge, heat-exchanger liquid, suction, outdoor-air and heat-exchanger middle thermistor errors. | | Safety devices | High-pressure switch and low-pressure switch faults. | | Compressor and current | Rotor-position detection, current trip, CT error and trip-terminal start-up error. |
| Indoor-unit error categories | | Group | Examples | | Configuration and memory | Model information abnormal, EEPROM access error and EEPROM deletion error. | | Sensors and drainage | Room-temperature thermistor, indoor heat-exchanger inlet/middle thermistor and drain abnormal. | | Communication | Indoor-to-outdoor communication, wired/simple remote-controller communication, transmission and parallel communication faults. | | Equipment | Indoor fan error, indoor microcomputer error and outdoor-unit error passed through to the indoor display. |
| | Reading the exact code: The exact LED flash count and lamp combination must be matched against the troubleshooting chapter. Do not diagnose from the category name alone. Record which LEDs are continuously lit, the flash count, flash speed and the indoor-unit address before resetting power. |
| 9. Recommended technician checks | | Step | Check | | 1 | Confirm complete model numbers, model-change codes, heat-pump or cooling-only configuration and refrigerant type. | | 2 | Record outdoor LED status, indoor lamp pattern, wired-controller error code and affected indoor-unit address before cycling power. | | 3 | Verify supply voltage, frequency, breaker size, earth, terminal tightness and voltage under load. | | 4 | Confirm power/signal wiring polarity, continuity, terminal-box connections, controller wiring and address settings. | | 5 | Review pipe layout, branch orientation, total length, height differences, pipe sizes, additional charge and outdoor pipe-length DIP settings. | | 6 | Inspect outdoor airflow, coil condition, fan operation, installation clearances and evidence of air recirculation. | | 7 | For pressure or temperature faults, confirm operating mode, ambient conditions, indoor airflow, refrigerant charge, valve positions, thermistor readings and pressure-switch state. | | 8 | For indoor faults, inspect filters, fan wheel, drain pan, drain pump, float switch, thermistors and EV-kit connection where fitted. |
| | Service note: This document is a consolidated field reference and does not replace the model-specific service, installation, control-system or troubleshooting manuals. Electrical and refrigerant work must be carried out by appropriately licensed personnel. |
| | GENERAL AIRSTAGE | J Series 6HP Product Reference |
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