GENERAL AIRSTAGE | Technical Reference
AOTH24-45KB Multi-Split Outdoor Units
Design & Technical Manual
Models AOTH24KBCA3, AOTH30KBTA4, AOTH36KBTA5 and AOTH45KBTA5 | R32 inverter heat pump
This article provides a quick technical reference to the AOTH24-45KB multi-split outdoor unit Design & Technical Manual. Use the full manual for detailed indoor-unit combinations, capacity tables, performance correction data, wiring diagrams, installation drawings and service procedures.
Important: These systems use R32 refrigerant and contain mains electrical circuits. Refrigerant, electrical, commissioning and service work must be completed by appropriately qualified personnel and in accordance with applicable local requirements.
1. Applies to
| Outdoor unit | Maximum indoor units | Connected capacity range | Refrigerant |
|---|
| AOTH24KBCA3 | 3 | 14,000-36,000 Btu/h | R32 |
| AOTH30KBTA4 | 4 | 25,000-49,000 Btu/h | R32 |
| AOTH36KBTA5 | 5 | 27,000-54,000 Btu/h | R32 |
| AOTH45KBTA5 | 5 | 34,000-62,000 Btu/h | R32 |
A minimum of 2 indoor units must be connected. The allowable indoor-unit capacity combinations are model-specific; confirm the exact combination in the manual before selection or installation.
2. Quick specifications
| Specification | AOTH24KBCA3 | AOTH30KBTA4 | AOTH36KBTA5 | AOTH45KBTA5 |
|---|
| Rated cooling capacity | 6.8 kW | 8.0 kW | 10.0 kW | 12.5 kW |
| Rated heating capacity | 8.0 kW | 9.6 kW | 12.0 kW | 13.2 kW |
| Dimensions (H x W x D) | 716 x 820 x 315 mm | 884 x 820 x 315 mm | 998 x 940 x 320 mm | 998 x 940 x 320 mm |
| Net weight | 46 kg | 59 kg | 74 kg | 74 kg |
| Cooling sound pressure | 46 dB(A) | 48 dB(A) | 52 dB(A) | 53 dB(A) |
| Heating sound pressure | 52 dB(A) | 54 dB(A) | 54 dB(A) | 55 dB(A) |
| Cooling operating range | -10 to 50 deg C |
| Heating operating range | -15 to 24 deg C |
| Power supply | 220-240 V~ 50 Hz | Outdoor-unit power supply |
Performance note: Published capacities are based on the manual's standard rating conditions. Actual capacity varies with indoor-unit combination, outdoor/indoor conditions, pipe length and height difference. Use the capacity and compensation tables in the manual for design calculations.
3. Connectable indoor units
The manual supports multiple indoor-unit styles including compact cassette, mini duct, slim duct, medium static pressure duct, wall mounted, floor console and ceiling units. Compatibility varies by outdoor model.
| Indoor type | Indoor model | 24KBCA3 | 30KBTA4 | 36KBTA5 | 45KBTA5 |
|---|
| Compact cassette | AUTH09KVLA / AUTH12KVLA / AUTH18KVLA | Yes | Yes | Yes | Yes |
| Mini duct | ARTH09KSLAP / ARTH12KSLAP / ARTH18KSLAP | Yes | Yes | Yes | Yes |
| Slim duct | ARTH09KLLAP / ARTH12KLLAP / ARTH18KLLAP | Yes | Yes | Yes | Yes |
| Medium static pressure duct | ARTH18KMTAP | Yes | Yes | Yes | Yes |
| Medium static pressure duct | ARTH24KMTAP | No | Yes | Yes | Yes |
| Wall mounted | ASTH07/09/12/14KMCD, ASTH09/12/18KMTD | Yes | Yes | Yes | Yes |
| Wall mounted | ASTH22KMTD / ASTH24KMTD / ASTH24KMTE | No | Yes | Yes | Yes |
| Floor console | AGTG09KVCA / AGTG12KVCA / AGTG14KVCA | Yes | Yes | No | No |
| Ceiling | ABTH18KRTA | Yes | Yes | Yes | Yes |
Combination check required: A connectable indoor model is not automatically valid in every capacity combination. Always confirm the exact combination table for the selected outdoor unit. The manual also contains restrictions for medium static pressure duct indoor units in some combinations.
4. Refrigerant piping and additional charge
| Item | AOTH24KBCA3 | AOTH30KBTA4 | AOTH36KBTA5 | AOTH45KBTA5 |
|---|
| Factory R32 charge | 1,800 g | 2,500 g | 3,000 g | 3,000 g |
| Pre-charge pipe length | 30 m | 40 m | 50 m | 50 m |
| Maximum total pipe length | 50 m | 70 m | 80 m | 80 m |
| Minimum total pipe length | 10 m | 15 m | 15 m | 15 m |
| Individual branch length | Minimum 5 m / Maximum 25 m each |
| Max. height difference: outdoor to indoor | 15 m |
| Max. height difference: indoor to indoor | 10 m |
| Additional charge rate | 20 g/m beyond the factory pre-charge length |
Additional refrigerant quick reference
| Model | Total pipe length and additional charge |
|---|
| AOTH24KBCA3 | 30 m or less: 0 g | 40 m: +200 g | 50 m: +400 g |
| AOTH30KBTA4 | 40 m or less: 0 g | 50 m: +200 g | 60 m: +400 g | 70 m: +600 g |
| AOTH36KBTA5 / AOTH45KBTA5 | 50 m or less: 0 g | 60 m: +200 g | 70 m: +400 g | 80 m: +600 g |
5. Design and installation reference
- Dimension drawings are provided separately for AOTH24KBCA3, AOTH30KBTA4, and the shared AOTH36KBTA5/AOTH45KBTA5 chassis.
- Installation-space requirements differ between the AOTH24/AOTH30 and AOTH36/AOTH45 chassis. Refer to the manual diagrams before finalising plant layout.
- The manual contains separate refrigerant circuit diagrams and wiring diagrams for each chassis configuration.
- Capacity compensation tables are provided for pipe length and height difference and should be considered when confirming design performance.
- Sound-pressure curves and the specified sound measurement point are included for acoustic assessment.
Installation environment: The manual identifies locations that are prohibited or require additional consideration, including combustible-gas risk, corrosive atmospheres, high salt exposure, strong wind, snow accumulation and areas where operating sound may affect neighbouring properties.
6. Electrical characteristics
| Model | Maximum operating current | Starting current | Circuit breaker | Power cable |
|---|
| AOTH24KBCA3 | 13.9 A | 7.8 A | 16 A | 2.5 mm² |
| AOTH30KBTA4 | 18.9 A | 8.9 A | 20 A | 2.5 mm² |
| AOTH36KBTA5 | 21.6 A | 11.0 A | 25 A | 4.0 mm² |
| AOTH45KBTA5 | 23.9 A | 15.8 A | 30 A | 4.0 mm² |
The manual lists a 1.5 mm² connection cable and 26 m limited wiring length. Cable and protection selection must still comply with applicable regional electrical requirements, and voltage drop is to be limited to less than 2%.
7. Demand control and function settings
Demand response modes
| Mode | Operation |
|---|
| DR Mode 1 | Compressor off. |
| DR Mode 2 | Cooling or heating continues, with half-hour electrical energy limited to no more than 50% of the energy that would be consumed at rated capacity. |
| DR Mode 3 | Cooling or heating continues, with half-hour electrical energy limited to no more than 75% of the energy that would be consumed at rated capacity. |
Demand-control wiring uses a locally supplied 4-core shielded signal cable, 0.5-1.5 mm², with a maximum cable length of 30 m. The manual references AS/NZS 5000.2, AS/NZS 3000 and AS/NZS 4755.1 requirements for this function.
Outdoor low-noise and current-limit settings
- SET1-4: Enables or disables outdoor-unit low-noise operation.
- SET2-1: Selects Low or Lower noise operation level.
- Low-noise operation and current limiting can reduce available cooling and heating capacity.
- Disconnect power before changing DIP-switch settings.
| Model | Full | Current-limit setting 1 | Current-limit setting 2 |
|---|
| AOTH24KBCA3 | Full | 12.0 A | 10.5 A |
| AOTH30KBTA4 | Full | 16.0 A | 12.5 A |
| AOTH36KBTA5 | Full | 16.0 A | 14.0 A |
| AOTH45KBTA5 | Full | 18.0 A | 16.0 A |
8. Commissioning, check run and service
Check run
The outdoor unit includes a check-run function to detect wiring errors between indoor and outdoor units. The manual also provides an automatic wiring correction function that can correct wiring allocation to match the connected refrigerant piping.
- Complete all refrigerant piping and electrical wiring before starting.
- Confirm the system has been leak-tested and charged with the specified refrigerant quantity.
- Record check-run results for future service reference.
- After automatic wiring correction, power must be disconnected or the breaker turned off, then restored before normal operation.
Test run
The test-run function is started from the outdoor control board. The manual instructs that the first test run is to be carried out in COOL. Cooling and heating modes cannot be changed while a test run is active; stop the test run before changing mode.
Error-code display
When a fault occurs, the red ERROR LED flashes at high speed. MONITOR LEDs A-F identify the affected location, and briefly pressing SW1 displays the fault code. The manual includes the complete code table for communication, sensor, inverter, IPM, pressure, fan, valve, compressor and expansion-valve faults.
Examples from the manual: 11.3 Serial communication error; 22.1 Indoor unit capacity error; 63.1 Inverter error; 65.3 IPM error; 86.4 High pressure switch 1 error; 97.3 Fan motor 1 error; 99.1 4-way valve error; 9A.1 expansion valve coil error; A1.1 discharge temperature error.
Pump down
A dedicated pump-down procedure is provided for relocation or disposal. The process uses SET1-2 and SW1 on the outdoor control board and requires pressure monitoring, closure of liquid and gas valves at the specified stages, and isolation of power when complete. Follow the full procedure in the manual rather than using this summary as a replacement.
9. What is included in the full manual
| Section | Content |
|---|
| 1 | Model lineup and indoor-unit connection patterns |
| 2 | Optional parts for indoor units: controllers, cassette grille, communications and interfaces |
| 3 | Optional parts for outdoor units |
| 4-5 | Indoor and outdoor installation precautions |
| 6 | Capacity tables covering combinations, cooling and heating performance |
| 7 | Capacity compensation for pipe length and height difference |
| 8 | Additional refrigerant charge calculation |
| 9-12 | Airflow, sound pressure, electrical characteristics and safety devices |
| 13 | Demand control / demand response |
| 14 | Function settings, low-noise operation and current limiting |
| 15 | Check run, test run, error codes and pump down |
| 16 | Supplied accessories |
Reference manual
Document: DR_MU034ES_01
Issue date: 17 June 2025
Title: Multi-split Outdoor Unit - Design & Technical Manual
Attach the full PDF to this Freshdesk solution so technicians can access the detailed combination, capacity, wiring and service information.
