General Assist Technical Reference
Wall-Mounted Split Installation Guide
ASTG18KMCA / ASTG22KMCA / ASTG24KMCA
For approved AOTG18KMCA / AOTG22KMCA / AOTG24KMCA R32 outdoor units
R32 flammable refrigerant: Installation, pressure testing, evacuation, charging and service work must be completed by qualified personnel using R32/R410A-rated tools and materials. Remove ignition sources, ventilate the work area and use an R32-compatible leak detector.
Minimum room area: The indoor-unit installation manual specifies a minimum room floor area of 2.06 m². The flare connection is to be positioned outdoors.
1. Quick specifications
| Item | Requirement |
|---|---|
| Refrigerant | R32 |
| Liquid pipe | 6.35 mm (1/4 in), minimum wall thickness 0.8 mm |
| Gas pipe | 12.70 mm (1/2 in), minimum wall thickness 0.8 mm |
| Maximum pipe length | 30 m |
| Maximum height difference | 20 m |
| Factory charge allowance | Up to 20 m of pipework |
| Additional refrigerant | 20 g/m above 20 m; +100 g at 25 m and +200 g at 30 m |
| Maximum total charge | 1,470 g |
| Cooling range | -10°C to 46°C |
| Heating range | -15°C to 24°C |
| Power supply | 1 phase, 240 V, 50 Hz; operating range 198–264 V |
| Model 18 power cable | 2.5 mm², 2 conductors plus earth |
| Models 22 and 24 power cable | 4.0 mm², 2 conductors plus earth |
| Interconnection cable | 1.5–2.5 mm², 3 conductors plus earth |
| Model 18 circuit breaker | 16 A |
| Models 22 and 24 circuit breaker | 20 A |
| Earth leakage breaker | 30 mA, 0.1 second or less |
Short pipework: Pipe runs shorter than 3 m may transfer outdoor-unit sound to the indoor unit and increase perceived operating noise.
2. Indoor-unit installation
| Clearance | Minimum |
|---|---|
| Above wall-hook bracket | 84 mm |
| Left side | 127 mm |
| Right side | 133 mm |
| Front clearance | 1,500 mm |
| Floor to indoor unit | 1,800 mm |
Human sensor: Approximate detection range is 7 m, 90° vertically and 100° horizontally. Keep heaters and large objects outside the detection area.
Indoor piping directions
Rear Right Bottom
| 1 | Select a strong, level wall with unrestricted airflow, suitable drainage and adequate service access. |
| 2 | Secure the wall-hook bracket level using at least five suitable fixing screws. |
| 3 | Cut a 65 mm wall hole with the outside edge 5–10 mm lower than the inside edge. |
| 4 | Fit a wall pipe and wall cap so wiring cannot contact raw metal. |
| 5 | Keep the drain hose below the refrigerant pipes and maintain continuous fall. |
| 6 | Engage the upper hooks first, then push the lower fittings onto both bottom hooks. |
Drainage: The drain hose must slope continuously downward. Do not lift the hose, create waves or leave the outlet submerged. Apply freeze protection where required.
3. Outdoor-unit installation
| Side | Minimum clearance |
|---|---|
| Rear | 100 mm |
| Left | 100 mm |
| Right | 250 mm |
| Front | 200 mm |
| Above | 600 mm |
| Below | 50 mm |
- Mount on a strong, level stand and keep tilt below 5°.
- Secure the outdoor unit against strong wind.
- Do not install directly on the ground.
- Keep at least three of the four horizontal directions open where possible.
- Do not use the accessory drain pipe or drain caps where outdoor temperature may fall to 0°C or below.
- Raise the unit and provide snow protection in heavy-snow areas.
4. Flare connections
| Pipe size | Torque |
|---|---|
| 6.35 mm (1/4 in) | 16–18 N·m |
| 12.70 mm (1/2 in) | 49–61 N·m |
Use R32/R410A-compatible flare tools. Maintain a bend radius of at least 70 mm and do not bend the same pipe section more than three times. The indoor manual states that the flare connection is to be located outdoors.
5. Nitrogen pressure test
Dry nitrogen only. Do not use refrigerant, oxygen, compressed air or flammable gas to pressurise the system.
| 1 | Confirm both service valves are closed and power remains isolated. |
| 2 | Introduce dry nitrogen to the liquid and suction lines simultaneously. |
| 3 | Pressurise the piping system to 4.15 MPa. |
| 4 | Leak-test all indoor and outdoor connections. |
| 5 | Confirm the system pressure does not decrease before releasing nitrogen safely. |
6. Vacuum and additional charging
| 1 | Connect a clean R32/R410A manifold and vacuum pump to the 3-way valve charging port. |
| 2 | Evacuate to -0.1 MPa / -76 cmHg and confirm 65 Pa / 500 microns on a vacuum gauge. |
| 3 | Continue operating the vacuum pump for at least 15 minutes. |
| 4 | Close the manifold and stop the pump. Stand for 1–2 minutes and confirm the gauge does not rise. |
| 5 | Crack the 3-way valve until pressure reaches approximately 0.1–0.2 MPa, then disconnect the hose. |
| 6 | Fully open both service valves and tighten all caps. |
| 7 | For pipework above 20 m, add liquid R32 by electronic scale at 20 g/m. |
| Cap | Torque |
|---|---|
| 1/4 in blank cap | 20–25 N·m |
| 1/2 in blank cap | 28–32 N·m |
| Charging-port cap | 12.5–16 N·m |
7. Electrical wiring
Match terminals 1, 2 and 3 between indoor and outdoor units and connect protective earth. Clamp cables by the outer sheath.
| Terminal screw | Torque |
|---|---|
| M3.5 | 0.8–1.0 N·m |
| M4 | 1.2–1.8 N·m |
| M5 | 2.0–3.0 N·m |
Route the demand-control signal cable away from the power-supply and interconnection cables to prevent control interference.
8. Test run and commissioning
Hold the indoor-unit MANUAL AUTO button for more than 10 seconds to begin forced cooling. The OPERATION and TIMER lamps flash together. Select HEAT using the remote controller for a heating test, which begins after approximately three minutes.
| Commissioning check | Done |
|---|---|
| Remote-controller operation confirmed | ☐ |
| Indicator lamps operate correctly | ☐ |
| Airflow louvres operate correctly | ☐ |
| Human sensor unobstructed and operating correctly | ☐ |
| Drainage test completed with no leaks | ☐ |
| No abnormal noise or vibration | ☐ |
| No refrigerant leakage detected | ☐ |
| Outdoor noise, airflow and drainage acceptable | ☐ |
| Customer shown operation and filter maintenance | ☐ |
9. Optional controls
| Option | Reference |
|---|---|
| Wired remote controller | UTY-RVNYN or UTY-RNNYN; communication kit required |
| Simple remote controller | UTY-RSNYN; communication kit required |
| External connect kit | UTY-XWZXZ5 |
| Communication kit | UTY-TWBXF1 |
Final handover: Leave the installation and operating manuals with the customer. Record any changed function settings, optional controls and additional refrigerant charge.
Based on Fujitsu General indoor installation manual Part No. 9320456023 and outdoor installation manual Part No. 9320394004-04. This simplified field reference does not replace the complete manuals, equipment rating labels or current Australian and New Zealand regulations.