GENERAL AIRSTAGE Technical Reference
ARTH65KHTA / ARTH72KHTA / ARTH90KHTA
Service manual, diagnostics, function settings and spare parts quick reference
R32 inverter ducted systems with AOTH65KBTA, AOTH65KRTA, AOTH72KRTA and AOTH90KRTA outdoor units
This article is a technician quick-reference based on the service manual and parts list for the ARTH65KHTA, ARTH72KHTA and ARTH90KHTA ducted range. Use the attached service manual for complete wiring diagrams, PCB layouts, control logic, detailed fault flowcharts and model-specific procedures.
Qualified service personnel only: These systems use R32 refrigerant and contain hazardous electrical voltages. Isolate the power supply before servicing and wait at least 5 minutes before touching electrical components. Refrigerant circuit work must only be performed by appropriately qualified personnel using equipment suitable for flammable refrigerants.
1. Model coverage
| Indoor unit | Outdoor unit | Power supply | Refrigerant |
|---|---|---|---|
| ARTH65KHTA | AOTH65KBTA | 220–240 V, 1N~, 50 Hz | R32 |
| ARTH65KHTA | AOTH65KRTA | 380–415 V, 3N~, 50 Hz | R32 |
| ARTH72KHTA | AOTH72KRTA | 380–415 V, 3N~, 50 Hz | R32 |
| ARTH90KHTA | AOTH90KRTA | 380–415 V, 3N~, 50 Hz | R32 |
Service manual revision: SR_AR081ES_03, dated 03 October 2025. The manual is structured into General Information, Technical Data and Parts List, Troubleshooting, Control and Functions, and Field Working.
2. Key specifications
| Specification | 65 | 72 | 90 |
|---|---|---|---|
| Rated cooling capacity | 18.0 kW | 20.0 kW | 22.4 kW |
| Rated heating capacity | 20.0 kW | 22.4 kW | 25.0 kW |
| High airflow | 1,139 L/s 4,100 m³/h | 1,194 L/s 4,300 m³/h | 1,400 L/s 5,040 m³/h |
| Standard static pressure | 60 Pa | 72 Pa | 72 Pa |
| Adjustable static pressure range | 60–200 Pa | ||
| Liquid pipe | Ø9.52 mm (3/8 in) | Ø12.70 mm (1/2 in) | Ø12.70 mm (1/2 in) |
| Gas pipe | Ø15.88 mm (5/8 in) | Ø19.05 mm (3/4 in) | Ø19.05 mm (3/4 in) |
| Factory refrigerant charge | 3.8 kg | 4.5 kg | 4.5 kg |
| Indoor unit dimensions | 360 × 1,400 × 850 mm (H × W × D) |
| Outdoor unit dimensions | 1,418 × 970 × 370 mm (H × W × D) |
| Factory pre-charge pipe length | 30 m |
| Maximum pipe length | 75 m |
| Maximum height difference | 30 m |
| Outdoor operating range – cooling | −15°C to 50°C |
| Outdoor operating range – heating | −20°C to 24°C |
R32 minimum room size: The service manual includes minimum floor-area requirements based on total refrigerant charge and installation height. Always check the applicable installation manual and total system charge before installation or refrigerant work.
3. Error codes
When an error is detected, a connected wired remote controller displays the error code. Where an indoor indicator or IR receiver is fitted, the Operation, Timer and Economy lamps can also identify the error by their blink pattern.
| Code | Description |
|---|---|
| 11 | Serial communication error / serial forward transfer error |
| 12 | Wired remote controller communication error |
| 15 | Automatic airflow adjustment error |
| 18 | External communication error |
| 22 | Indoor unit capacity error |
| 23 | Refrigerant combination error |
| 26 | Wired remote controller address setting error |
| 29 | Connected unit number error |
| 32 | Indoor unit Main PCB error |
| 33 | Indoor unit motor electricity consumption detection error |
| 35 | MANUAL AUTO button error |
| 39 | Power supply error of indoor unit fan motor |
| 3A | Indoor unit communication circuit error |
| 41 / 42 | Indoor unit thermistor error |
| 51 | Indoor unit fan motor error |
| 53 | Drain pump error |
| 5U | Indoor unit error |
| 61.5 | Outdoor unit missing phase wire error |
| 62 | Outdoor unit Main PCB communication error |
| 63 | Inverter error |
| 64 | PFC circuit error |
| 65 | IPM error |
| 71 / 72 / 73 / 74 / 76 / 77 | Outdoor unit thermistor error – exact code identifies the relevant sensor/circuit |
| 84 | Current sensor error |
| 86 | High pressure switch error |
| 94 | Trip detection |
| 95 | Compressor motor control error |
| 97 / 98 | Outdoor unit fan motor error |
| 99 | 4-way valve error |
| A1 | Discharge temperature error |
| A3 | Compressor temperature error |
| AC | Heat sink temperature error |
Checking stored error memory
- Stop the air conditioner and disconnect the power supply.
- Reconnect the power supply.
- During the initial “3 minutes ST” period, start operation and press TEST RUN on the remote controller, or press the indoor/receiver MANUAL AUTO button for 10 seconds or more where applicable.
- The stored error is displayed during this period. The manual states the available display window is approximately 2 minutes 20 seconds after power is restored.
Erase error memory: While the stored error is displayed, press MANUAL AUTO for a manual erase where the applicable indicator unit is fitted. The memory also clears automatically after at least 2 hours of normal error-free operation, excluding Fan mode.
4. Service diagnostic reference
| Component | Service check |
|---|---|
| Compressor terminals | R(U) = Red, S(V) = White, C(W) = Black. Outdoor inverter PCB outputs are P400 (U), P401 (V), P402 (W). |
| 65KBTA compressor winding | 0.676 Ω ±8% at 20°C. A reading of 0 Ω or infinity indicates a defective compressor. |
| 65KRTA compressor winding | 1.160 Ω ±8% at 20°C. |
| 72 / 90KRTA compressor winding | 0.950 Ω ±8% at 20°C. |
| Outdoor EEV coil | Measure from Red common to Blue, Orange, Yellow and White: 46 Ω ±3 Ω at 20°C. The manual specifies a 12 V DC PCB drive check. |
| 4-way valve coil | Coil resistance: approximately 1,970 Ω at 20°C. Refer to the model-specific PCB diagram before testing. |
| High pressure switch | Connector P770. Contact changes Short → Open at 4.2 MPa (+0 / −0.15 MPa) and Open → Short at 3.2 ±0.15 MPa. |
| Outdoor fan motor | With power isolated, confirm free fan rotation. The manual instructs checking Vm to GND; if short-circuited below 300 kΩ, replace the outdoor fan motor and controller PCB. |
For any fault code: use the detailed Chapter 3 flowchart before replacing components. The manual provides checks for wiring, power supply, thermistors, fans, refrigerant circuit conditions, PCB signals and individual component failures for each code.
5. Common indoor function settings
Important: Incorrect function settings can cause product malfunction. After changing a function setting, switch the power off, wait at least 30 seconds, then switch the power back on for the setting to become active.
| Function | Purpose | Useful settings |
|---|---|---|
| 11 | Filter sign interval | 00 = 2,500 h; 01 = 4,400 h; 02 = 1,250 h; 03 = no indication |
| 26 | Static pressure | 06 = 60 Pa through to 20 = 200 Pa; 31 = standard (65: 60 Pa / 72 & 90: 72 Pa); 32 = automatic airflow adjustment |
| 30 / 31 | Indoor room temperature sensor correction | Use only where temperature correction is required for the installation. Refer to the manual for the full correction-value table. |
| 35 / 36 | Wired controller sensor correction | Correction for room temperature measured at the wired controller. Refer to the manual for values. |
| 40 | Auto restart | 00 = Enable; 01 = Disable |
| 42 | Room temperature sensor switching | 00 = indoor unit sensor; 01 = both indoor unit and wired controller sensors |
| 43 | Cold air prevention | 00 = Enable; 01 = Disable |
| 46 | External input control | 00 = Operation/Stop mode 1; 02 = Forced stop; 03 = Operation/Stop mode 2 |
| 48 | Room temperature sensor switching (Aux.) | 00 = both; 01 = wired remote controller only. Function 42 must be set to 01 for this function to operate. |
| 49 | Indoor fan energy saving in cooling | 00 = Disable; 01 = Enable; 02 = controlled by compatible remote controller |
| 60 | External output terminal function | 00 = operation status; 09 = error status; 10 = fresh air control; 11 = external device |
Outdoor local settings
Outdoor unit settings are accessed from the outdoor control PCB using the MODE, SELECT, ENTER and EXIT switches. The service manual includes the full local-setting procedure and settings for functions including low-noise and peak-cut operation.
6. Common service parts
Part numbers below are taken from the supplied service manual and parts list. Parts information can change; always confirm the latest supersession and availability before ordering.
Indoor unit parts
| Part | Part No. | Applies to |
|---|---|---|
| Main PCB | 9712270497 | ARTH65KHTA |
| Main PCB | 9712270503 | ARTH72KHTA |
| Main PCB | 9712270510 | ARTH90KHTA |
| Power supply PCB / service unit | 9712996779 | ARTH65KHTA |
| Power supply PCB / service unit | 9712996786 | ARTH72KHTA |
| Power supply PCB / service unit | 9712996793 | ARTH90KHTA |
| DC fan motor | 9603482015 | ARTH65KHTA |
| DC fan motor | 9604278006 | ARTH72KHTA |
| DC fan motor | 9603567019 | ARTH90KHTA |
| Sirocco fan assembly | 9381440016 | All three indoor models – quantity 2 |
| Evaporator total assembly | 9383816376 | ARTH65KHTA |
| Evaporator total assembly | 9383816697 | ARTH72KHTA |
| Evaporator total assembly | 9383816680 | ARTH90KHTA |
| Communication PCB | 9710019005 | All three indoor models |
| Room temperature thermistor | 9703299278 | All three indoor models |
| Pipe temperature thermistor | 9900892012 | All three indoor models |
| Wired remote controller assembly | 9709335314 | All three indoor models |
Outdoor unit parts
| Part | Part No. | Applies to |
|---|---|---|
| Compressor | 9810622006 | AOTH65KBTA |
| Compressor | 9810628008 | AOTH65KRTA |
| Compressor | 9811004009 | AOTH72KRTA / AOTH90KRTA |
| Main PCB | 9711435255 | AOTH65KBTA |
| Main PCB | 9711435262 | AOTH65KRTA |
| Main PCB | 9711435279 | AOTH72KRTA |
| Main PCB | 9711435286 | AOTH90KRTA |
| Inverter PCB / service unit | 9709688076 | AOTH65KBTA |
| Inverter PCB / service unit | 9712996687 | AOTH65KRTA |
| Inverter PCB / service unit | 9712996694 | AOTH72KRTA / AOTH90KRTA |
| Condenser assembly | 9374420650 | AOTH65KBTA / AOTH65KRTA |
| Condenser assembly | 9374420841 | AOTH72KRTA / AOTH90KRTA |
| DC fan motor | 9604245015 | All outdoor models – quantity 2 |
| Propeller fan | 9383336003 | AOTH65KBTA / AOTH65KRTA – quantity 2 |
| Propeller fan | 9383337000 | AOTH72KRTA / AOTH90KRTA – quantity 2 |
| Expansion valve coil | 9970209000 | AOTH65KBTA / AOTH65KRTA |
| Expansion valve coil | 9970249006 | AOTH72KRTA / AOTH90KRTA |
| Expansion valve assembly | 9370947434 | AOTH65KBTA / AOTH65KRTA |
| Expansion valve assembly | 9370947465 | AOTH72KRTA / AOTH90KRTA |
| 4-way valve assembly | 9374425839 | AOTH65KBTA / AOTH65KRTA |
| 4-way valve assembly | 9374425822 | AOTH72KRTA / AOTH90KRTA |
| High pressure switch | 9900186029 | All outdoor models |
| Outdoor temperature thermistor | 9900565046 | All outdoor models |
| Compressor temperature thermistor | 9900985028 | All outdoor models |
7. Compatible controllers and optional parts
| Accessory | Model | Connection / purpose |
|---|---|---|
| Wired Remote Controller – Touch Panel | UTY-RVRY | Non-polar 2-wire, Y1/Y2 |
| Wired Remote Controller – Touch Panel / zone capable | UTY-RNRT | Non-polar 2-wire, Y1/Y2 |
| Wired Remote Controller – Touch Panel | UTY-RNRYT | Non-polar 2-wire, Y1/Y2 |
| Wired Remote Controller | UTY-RVNYN | Polar 3-wire, Y1/Y2/Y3 |
| Simple Remote Controller | UTY-RSRYT / UTY-RHRYT | Non-polar 2-wire, Y1/Y2 |
| Simple Remote Controller | UTY-RSNYN | Polar 3-wire, Y1/Y2/Y3 |
| IR Receiver Kit with wireless controller | UTY-LBTYM | Connects to CN48 on indoor Main PCB |
| Remote Sensor Unit | UTY-XSZXT | Connects to CN8 |
| Long-life Filter | UTD-LFKA | Indoor unit filter option |
| Drain Pump Unit | UTZ-PX1NAB | Connects to CN9 and CN71 |
| External Connect Kit | UTY-XWZXZG | Control output, CN47 |
| External Input / Output PCB | UTY-XCSX | Connects to CN65 or CN75; bracket UTZ-GXNA |
| Zone Control Interface – 3-wire | UTY-CDPXZC / UTY-CDPXZD | Polar 3-wire, Y1/Y2/Y3 |
| Zone Control Interface – 2-wire | UTY-CDRXZC / UTY-CDRXZD | Non-polar 2-wire, Y1/Y2 |
| Modbus Converter | UTY-VMSX | UART connection via CN65 or CN75 |
| KNX Converter | UTY-VKSX | UART connection via CN65 or CN75 |
| Network Converter | UTY-VTGX | Connects the single-split system to a VRF network; Y1/Y2 |
| External Switch Controller | UTY-TERX | External sensor/switch control via Y1/Y2 |
| Outdoor External Connect Kit | UTY-XWZXZ3 | Outdoor external input/output functions |
| L-type piping kit | UTP-FX06A | Gas-pipe connection option for 72 and 90 models |
8. What is covered in the full service manual
| General Information | Specifications, dimensions, installation clearances, maintenance access and R32 minimum room size. |
| Technical Data & Parts | Exploded parts, accessories, options, refrigerant circuit diagrams, wiring diagrams and PCB diagrams. |
| Troubleshooting | Error memory, error codes, fault-by-fault flowcharts, troubleshooting without error codes, compressor/EEV/fan checks and thermistor resistance tables. |
| Control & Functions | Compressor control, auto changeover, fan control, timers, defrost, EEV control, drain pump control, demand response, peak cut, low-noise mode and system protections. |
| Field Working | Indoor and outdoor function settings plus external input/output wiring, configuration and control behaviour. |
Freshdesk attachments: Attach the complete ARTH65–90KHTA service manual and the matching parts list to this solution so technicians can open the original diagrams and detailed troubleshooting procedures when required.
Technical note: This article is a quick-reference summary. Always verify model, serial number, current service documentation and the latest spare-part supersession before diagnosis, repair or ordering.