ASTG09KMCA / ASTG12KMCA Service Reference

Service and troubleshooting reference for the GENERAL AIRSTAGE wall-mounted split systems listed below.

Indoor unitOutdoor unitCoolingHeating
ASTG09KMCAAOTG09KMCA2.50 kW3.20 kW
ASTG12KMCAAOTG12KMCA3.50 kW3.70 kW
Quick identification
240 V, 50 Hz inverter split system using R32. Factory refrigerant charge is 850 g. Maximum piping length is 20 m and maximum height difference is 15 m.

1. Key Specifications

Specification09KMCA12KMCA
Cooling input0.51 kW0.86 kW
Heating input0.65 kW0.81 kW
High airflow750 m³/h770 m³/h
Indoor dimensions (H × W × D)268 × 840 × 203 mm
Outdoor dimensions (H × W × D)540 × 790 × 290 mm
Liquid pipe1/4 in. (6.35 mm)
Gas pipe3/8 in. (9.52 mm)

2. Compressor Operating Range

ModelCoolingHeatingDry
AOTG09KMCA20–74 rps20–100 rps25–35 rps
AOTG12KMCA20–88 rps20–105 rps27–35 rps

3. Test Operation and Forced Cooling

Test run
  1. Press and hold the indoor unit MANUAL AUTO button for more than 10 seconds.
  2. The OPERATION and TIMER indicators flash simultaneously during the cooling test run.
  3. If HEAT is selected from the remote controller, the heating test run begins after approximately 3 minutes.
  4. Press START/STOP on the remote controller to end the test operation.
Restart delay
After the compressor stops, it will not restart for approximately 2 minutes 20 seconds. When changing from cooling to heating, the 4-way valve is switched after this delay.

Forced cooling: Holding MANUAL AUTO for 10 seconds or more starts forced cooling regardless of room temperature. The OPERATION and TIMER lamps flash 1 second ON / 1 second OFF. Forced cooling automatically releases after 60 minutes.

4. Function Settings

Function settings are changed using the wireless remote controller. After changing settings, turn power off, wait at least 30 seconds, then turn power back on for the new setting to become active.

FunctionNo.Settings
Filter sign interval1100 Standard / 01 Long / 02 Short / 03 No indication
Cooling room temperature correction3000 Standard / 01 Slightly lower / 02 Lower / 03 Higher
Heating room temperature correction3100 Standard / 01 Lower / 02 Slightly higher / 03 Higher
Auto restart4000 Enable / 01 Disable
Room temperature sensor switching4200 No / 01 Yes
Remote controller signal code4400 A / 01 B / 02 C / 03 D
External input control4600 Operation/Stop / 01 Prohibited / 02 Forced stop
Indoor fan energy saving in cooling4900 Disable / 01 Enable

5. Error Code Quick Reference

The indoor unit displays faults by flashing the OPERATION and TIMER indicators. Where a wired remote controller is fitted, the corresponding error code is displayed directly.

CodeFault
11Serial communication error
12Wired remote controller communication error
23Combination error
32Indoor unit PCB model information error
35Manual auto switch error
41Room temperature sensor error
42Indoor heat exchanger middle temperature sensor error
51Indoor unit fan motor error
62Outdoor unit main PCB model information error
63Inverter error
64PFC circuit error
65Trip terminal L error
71Discharge temperature sensor error
73Outdoor heat exchanger liquid temperature sensor error
74Outdoor temperature sensor error
84Current sensor error
94Trip detection
95Compressor rotor position detection error
97Outdoor unit fan motor error
994-way valve error
A1Discharge temperature error

6. Common Service Checks

Serial communication – E:11

  • Check indoor/outdoor interconnection wiring for loose, removed or incorrect connections.
  • Confirm outdoor supply is approximately AC198–264 V at L–N.
  • Reverse-transfer serial signal at outdoor L–3 should swing approximately AC90–270 V.
  • Forward-transfer signal at outdoor N–3 should swing approximately AC30–130 V.

Thermistor faults

For room, indoor heat exchanger, discharge, outdoor heat exchanger and outdoor air thermistor faults, first check the connector and wiring, then disconnect the thermistor and compare its resistance against the service manual resistance table. The thermistor input circuit uses a DC5 V reference.

Compressor winding

For AOTG09/12KMCA, the service information lists compressor winding resistance as approximately 1.44 Ω at 20°C. Measure between each compressor terminal. A reading of zero or infinite resistance indicates an abnormal compressor.

Electrical safety
These checks involve mains voltage, inverter circuitry and stored DC voltage. Testing must only be completed by appropriately qualified service personnel using suitable test equipment and safe isolation procedures.

7. Key Spare Parts

ComponentPart number
Indoor Main PCB – ASTG09KMCA9709622018
Indoor Main PCB – ASTG12KMCA9709622025
Indoor thermistor assembly9900627010
Indoor display assembly9709642016
Indoor fan motor9603318017
Crossflow fan assembly9316830004
Outdoor Main PCB – AOTG09KMCA9709680049
Outdoor Main PCB – AOTG12KMCA9709680056
Outdoor thermistor9900565008
Outdoor thermistor assembly9900628000
Outdoor fan motor9602864010
Compressor assembly9320416003
Expansion valve coil9970095030
4-way valve assembly9320412005
4-way valve solenoid9970110023
Parts note
Always confirm current supersession and stock status before ordering. The part numbers above are those shown in the source service manual for these models.

Technician Summary

  • ASTG09KMCA pairs with AOTG09KMCA; ASTG12KMCA pairs with AOTG12KMCA.
  • R32 refrigerant, 850 g factory charge, 1/4 in. liquid and 3/8 in. gas piping.
  • Maximum piping length 20 m; maximum height difference 15 m.
  • MANUAL AUTO held for more than 10 seconds starts the test / forced cooling sequence.
  • After changing function settings, power-cycle the system after waiting at least 30 seconds.
  • Use the indoor flash pattern or wired remote controller code to identify the fault before replacing components.
  • Confirm current spare-part supersessions before ordering.
Technical note: This article is a condensed service reference based on the ASTG09/12KMCA service instruction and service manual. For detailed diagnostic flowcharts, PCB schematics, thermistor resistance tables, disassembly procedures and complete parts breakdowns, refer to the applicable full service documentation.