General Assist Technical Reference
ASTG18LVCA / AOTG18LVC Operation Manual
Wall Mounted Inverter Air Conditioner
Operating guidance, heating and cooling modes, remote control functions, timers, 10 °C Heat, airflow adjustment, cleaning, defrost operation and basic troubleshooting.
Applies to: ASTG18LVCA wall-mounted indoor unit and associated AOTG18LVC outdoor unit. The operating manual is Part No. 9318657005-03 and covers R410A wall-mounted inverter systems.
Safety: Installation, maintenance and servicing must only be carried out by qualified personnel. If there is a burning smell or other malfunction, stop operation, switch off the electrical breaker and contact authorised service personnel.
1. Quick start
| Function | What to do |
|---|---|
| Start / stop | Press START/STOP. |
| Select mode | Press MODE to cycle through AUTO, COOL, DRY, HEAT and FAN. |
| Set temperature | Use SET TEMP. AUTO: 18–30 °C, Heating: 16–30 °C, Cooling / Dry: 18–30 °C. |
| Fan speed | Press FAN to select AUTO, HIGH, MED, LOW or QUIET. |
| 10 °C Heat | Press 10°C HEAT to maintain the room at approximately 10 °C and help prevent the temperature falling too low. |
| Economy | Press ECONOMY. On a single-type system, maximum output is approximately 70% of normal operation. |
2. Remote controller
The wireless remote controller operates the indoor unit from approximately 7 metres when pointed toward the signal receiver. A beep confirms that the signal has been received.
- MODE: AUTO / COOL / DRY / HEAT / FAN.
- 10°C HEAT: activates low-temperature heating protection.
- SET TEMP: changes the thermostat setting.
- FAN: AUTO / HIGH / MED / LOW / QUIET.
- ECONOMY: enables reduced-output energy-saving operation.
- SLEEP: sets a timed shutdown with gradual temperature adjustment.
- TIMER MODE / TIMER SET: sets ON, OFF and PROGRAM timer operation.
- SET: adjusts vertical airflow direction.
- SWING: starts or stops automatic up/down louvre swing.
Remote batteries: Use two R03 / LR03 batteries. If the operating range becomes noticeably shorter, replace the batteries and press the RESET button with a small pointed object.
3. Operating modes
| Mode | Operation |
|---|---|
| AUTO | The unit selects Cooling, Dry, Heating or Monitor operation according to the difference between the room temperature and the thermostat setting. |
| HEAT | Used to warm the room. The indoor fan may run at very low speed for approximately 3–5 minutes after heating starts while the indoor heat exchanger warms. |
| COOL | Used to cool the room. |
| DRY | Provides gentle cooling while dehumidifying. Fan speed cannot be manually changed in Dry mode and the fan may stop periodically. |
| FAN | Circulates room air without heating or cooling. |
4. Timer operation
Before using timer functions, set the remote controller clock to the correct current time.
| Timer | Operation |
|---|---|
| ON timer | Starts the air conditioner at the selected time. |
| OFF timer | Stops the air conditioner at the selected time. |
| PROGRAM timer | Combines one ON and one OFF timer transition within a 24-hour period. |
| SLEEP – Heating | The thermostat setting is lowered 1 °C every 30 minutes until it has been reduced by 4 °C, then maintained until the stop time. |
| SLEEP – Cooling / Dry | The thermostat setting is raised 1 °C every 60 minutes until it has risen by 2 °C, then maintained until the stop time. |
5. 10 °C Heat operation
The 10 °C Heat function is designed to help prevent the room temperature from falling too low.
- Press 10°C HEAT on the remote controller.
- The unit will maintain the room at approximately 10 °C when heating is required.
- Press START/STOP to cancel the function.
Function limitation: While 10 °C Heat is operating, only airflow direction adjustment can be used. Heating will not operate when the room temperature is already high enough.
6. Airflow direction and swing
Vertical airflow is adjusted using the remote controller. Horizontal right/left airflow is adjusted manually only after the air conditioner has been stopped completely.
- Cooling / Dry: vertical positions 1–3.
- Heating: vertical positions 4–6.
- Automatic setting: Cooling / Dry defaults to horizontal position 1; Heating defaults to downward position 5.
- Swing: Cooling / Dry swings between positions 1 and 3; Heating swings between positions 3 and 6.
- During Cooling / Dry, do not leave the airflow louvres in the heating range for extended periods. If left there for more than approximately 30 minutes, they automatically return to position 3.
Do not move the vertical airflow louvres by hand. Use the remote controller SET button. Stop the air conditioner completely before manually adjusting the right/left louvres.
7. Economy and Manual Auto operation
Economy operation
Press ECONOMY while the system is operating. On a single-type air conditioner, maximum output is approximately 70% of normal cooling or heating operation. The thermostat setting is automatically adjusted to reduce unnecessary heating or cooling.
Manual Auto
If the remote controller is lost or unavailable, press the indoor unit MANUAL AUTO button for approximately 3 seconds. The unit operates in AUTO mode with AUTO fan speed and a standard thermostat setting of 24 °C.
Important: Holding MANUAL AUTO for more than 10 seconds starts forced cooling operation intended for authorised service personnel.
8. Cleaning and care
Stop the air conditioner and turn off the electrical breaker before cleaning.
- Clean the standard air filters approximately every 2 weeks during normal use.
- Remove dust with a vacuum cleaner or wash the filters using neutral detergent and warm water.
- Allow filters to dry completely in a shaded place before refitting.
- Do not use water hotter than 40 °C, abrasive cleaners, benzene or thinner on the indoor unit.
- If the unit will be shut down for one month or longer, operate Fan mode for approximately half a day first to dry the internal components.
Air cleaning filter
| Filter | Part number / maintenance |
|---|---|
| Air Cleaning Filter | UTR-FA16-3 — clean approximately every 6 months. The manual recommends replacement approximately every 3 years to maintain air-cleaning performance. |
9. Automatic defrost operation
During heating in low outdoor temperatures and high humidity, frost may form on the outdoor unit. The system automatically enters a defrost cycle to restore heating performance.
- Automatic defrosting typically lasts approximately 7–15 minutes.
- The OPERATION indicator flashes and the DEFROST indicator lights during defrost.
- Heating is temporarily interrupted during the defrost cycle.
- Steam or water from the outdoor unit during heating or defrost can be normal.
10. Troubleshooting
| Symptom | Check / explanation |
|---|---|
| Does not restart immediately | A protection delay of approximately 3 minutes may prevent compressor operation after stopping or restoring power. |
| Water-flow or refrigerant noise | Refrigerant movement can be audible during operation and for a short period after starting or stopping. |
| Sizzling noise in Heating | This can occur during Automatic Defrosting and is not necessarily a fault. |
| Mist from indoor unit | A fine mist can occur during Cooling / Dry when room air is rapidly cooled. |
| Steam or water from outdoor unit | This can occur during Heating and Automatic Defrosting. |
| Weak or stopped airflow | This may be normal at the start of Heating, during defrost, in Dry mode, QUIET mode or AUTO monitor operation. |
| Does not operate | Check the circuit breaker, power supply, fuse / breaker status and whether a timer is active. |
| Poor cooling or heating | Check for dirty filters, blocked intake/outlet, incorrect set temperature, open doors/windows, strong sunlight, room heat loads and QUIET operation. |
| Remote control response is incorrect | Check battery condition and battery polarity. |
Service required: If the problem persists, a burning smell is detected, or the OPERATION and TIMER indicators flash abnormally, stop operation, turn off the electrical breaker and contact authorised service personnel.
11. Power interruption / Auto Restart
After a power interruption, the air conditioner automatically restarts in its previous operating mode when power is restored. If the interruption occurs during timer operation, the timer is reset and the TIMER indicator may flash.
Reference: Operating Manual Part No. 9318657005-03 — wall-mounted R410A inverter air conditioner range including ASTG18LVCA.