GENERAL AIRSTAGE Technical Reference
ASTG09KMTC / ASTG12KMTC Service Reference
Specifications, refrigerant circuit, error codes, PCB data and optional controls
Indoor units: ASTG09KMTC / ASTG12KMTC | Outdoor units: AOTG09KMTC / AOTG12KMTC
This reference consolidates key service information for the KMTC wall-mounted R32 inverter systems. Use the model-specific service and installation documentation where a complete commissioning, repair or diagnostic procedure is required.
Qualified service personnel only: Isolate mains power before accessing electrical components. Refrigerant work must be carried out using procedures and equipment suitable for R32 refrigerant.
1. Model applicability
| System size | Indoor unit | Outdoor unit |
|---|---|---|
| 2.5 kW class | ASTG09KMTC | AOTG09KMTC |
| 3.5 kW class | ASTG12KMTC | AOTG12KMTC |
2. Key specifications
| Item | ASTG09KMTC / AOTG09KMTC | ASTG12KMTC / AOTG12KMTC |
|---|---|---|
| Power supply | 240 V ~ 50 Hz, outdoor unit supply | |
| Available voltage range | 198-264 V | |
| Cooling capacity | 2.5 kW rated 0.9-3.6 kW range | 3.5 kW rated 0.9-4.1 kW range |
| Heating capacity | 3.2 kW rated 0.9-5.3 kW range | 4.1 kW rated 0.9-6.1 kW range |
| Rated input - cooling | 0.53 kW | 0.89 kW |
| Rated input - heating | 0.66 kW | 0.79 kW |
| Maximum operating current | Cooling 6.0 A Heating 7.5 A | Cooling 6.5 A Heating 9.0 A |
| Indoor dimensions | 270 x 834 x 222 mm (H x W x D) | |
| Outdoor dimensions | 542 x 799 x 290 mm (H x W x D) | |
| Indoor net weight | 10 kg | |
| Outdoor net weight | 32 kg | |
Outdoor operating range: Cooling -10°C to 46°C; Heating -15°C to 24°C. Protective functions may operate when equipment is used outside the specified range.
3. Refrigerant and piping
| Refrigerant | R32 |
| Factory charge | 850 g |
| Pre-charge pipe length | 15 m |
| Maximum pipe length | 20 m |
| Maximum height difference | 15 m |
| Liquid pipe | 6.35 mm (1/4 in) flare |
| Gas pipe | 9.52 mm (3/8 in) flare |
| Refrigerant oil | POE (RB68A), 340 cm3 |
The refrigerant circuit contains the compressor, 4-way valve, outdoor heat exchanger, expansion valve, strainers, 2-way and 3-way service valves, indoor heat exchanger and associated thermistors.
Thermistors shown in the circuit
- ThD - Discharge temperature
- ThO - Outdoor temperature
- ThHO - Outdoor heat exchanger outlet temperature
- ThHM - Indoor heat exchanger middle temperature
- ThR - Room temperature
- ThPI - Pipe temperature
4. PCB and electrical service data
Indoor unit
| Item | ASTG09KMTC | ASTG12KMTC |
|---|---|---|
| Control unit | EZ-01836HSE | EZ-01837HSE |
| Main PCB identification | K18RA-1806HSE-C1 | K18RA-1807HSE-C1 |
Indoor thermistor reference - CN1
| Sensor | 0°C | 20°C | 30°C |
|---|---|---|---|
| Pipe thermistor | 176.0 kOhm | 62.9 kOhm | 39.6 kOhm |
| Room thermistor | 33.6 kOhm | 12.5 kOhm | 8.0 kOhm |
Outdoor unit
| Item | AOTG09KMTC | AOTG12KMTC |
|---|---|---|
| Inverter assembly | EZ-018FHUE | EZ-0187HUE |
| Main PCB identification | K17LG-1803HUE-C1 | K17LG-1800HUE-C1 |
| Compressor winding resistance | 1.975 Ohm at 25°C (U-V / V-W / U-W) | |
| 4-way valve coil | 2,780 Ohm at 20°C | |
| Expansion valve coil | 46.0 Ohm at 20°C | |
Outdoor thermistor reference
| Sensor | 0°C | 20°C | 30°C |
|---|---|---|---|
| Discharge thermistor | 168.6 kOhm | 62.6 kOhm | 40.0 kOhm |
| Outdoor temperature thermistor | 35.2 kOhm | 12.6 kOhm | 8.0 kOhm |
| Pipe thermistor | 16.1 kOhm | 6.0 kOhm | 3.8 kOhm |
5. Error indication and common codes
When a wireless controller is used, the indoor indicator lamps display the fault as a flashing pattern. With a compatible wired controller, the error code is shown directly on the controller display. Error indication is displayed during operation.
Indoor display: OPERATION lamp = green, TIMER lamp = orange, ECONOMY lamp = green. The number in brackets in the service table represents the number of flashes.
| Code | Description |
|---|---|
| 11 | Serial communication error |
| 12 | Wired remote controller / server room control communication error |
| 15 | Check run unfinished / automatic airflow adjustment error |
| 18 | External communication error |
| 23 | Combination error |
| 32 | Indoor unit PCB model information error |
| 35 | Manual auto switch error |
| 41 | Room temperature sensor error |
| 42 | Indoor heat exchanger middle temperature sensor error |
| 44 | Human sensor error |
| 51 | Indoor unit fan motor error |
| 62 | Outdoor unit main PCB model information / communication error |
| 63 | Inverter error |
| 64 | Active filter / PFC circuit error |
| 65 | Trip terminal L error |
| 71 | Discharge temperature sensor error |
| 73 | Outdoor heat exchanger liquid temperature sensor error |
| 74 | Outdoor temperature sensor error |
| 84 | Current sensor error |
| 94 | Trip detection |
| 95 | Compressor rotor position detection error |
| 97 | Outdoor unit fan motor 1 error |
| 99 | 4-way valve error |
| A1 | Discharge temperature error |
Important: An error code identifies the detected condition; it does not automatically identify the failed part. Confirm wiring, connectors, sensor values and supply conditions before replacing components.
6. Controllers and optional interfaces
| Accessory | Model | Notes |
|---|---|---|
| Wired remote controller | UTY-RNRYZ* | Non-polar 2-wire. Communication kit required. |
| Wired remote controller | UTY-RLRY | Non-polar 2-wire. Communication kit required. |
| Simple remote controller | UTY-RSRY | Non-polar 2-wire. Communication kit required. |
| Simple remote controller | UTY-RHRY | Non-polar 2-wire. Communication kit required. |
| Communication kit | UTY-TWRXZ2 | Required to connect a non-polar 2-core wired controller. |
| External input/output PCB | UTY-XCSXZ2 | Provides connection to external devices. |
| External connect kit | UTY-XWZXZ5 | Communication kit also required. |
| Wireless LAN adapter | UTY-TFSXF3 | Provides mobile-device control. |
Controller note: The service manual states that group control using the wired remote controller is prohibited for this product.
7. Standard accessories
The indoor unit is supplied with the operating manual, installation manual, wall hook bracket, wireless remote controller, remote controller holder, two batteries, five large tapping screws, two small tapping screws, cloth tape, two filter holders and one air cleaning filter set. The outdoor unit accessory set includes an installation manual, drain pipe and cable tie.
Technical information should be confirmed against the latest GENERAL AIRSTAGE service and installation documentation before service work is performed.