General Assist Technical Reference
Wall-Mounted Split Installation Guide
ASTG18KMTC / ASTG22KMTC / ASTG24KMTC
For approved AOTG18KMTC / AOTG22KMTC / AOTG24KMTC 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.
Room-area requirement: Confirm the total refrigerant charge against the minimum room-area table before installation. Mechanical connections must remain accessible for maintenance.
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 | 25 m |
| Factory charge allowance | Up to 15 m of pipework |
| Additional refrigerant | 20 g/m above 15 m; +100 g at 20 m, +200 g at 25 m and +300 g at 30 m |
| 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 |
| Power cable | 2.5 mm², 2 conductors plus earth |
| Interconnection cable | 1.5–2.5 mm², 3 conductors plus earth |
| Model 18 breaker | 16 A |
| Models 22 and 24 breaker | 20 A |
| Earth leakage breaker | 30 mA |
Minimum room area
| Total refrigerant charge | Minimum room area |
|---|---|
| 1.22 kg or less | No minimum specified by this table |
| Over 1.22 kg to 1.23 kg | 1.45 m² |
| Over 1.23 kg to 1.50 kg | 2.15 m² |
| Over 1.50 kg to 1.75 kg | 2.92 m² |
| Over 1.75 kg to 2.00 kg | 3.82 m² |
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 unit | 71 mm |
| Left side | 117 mm |
| Right side | 160 mm |
| Front clearance | 1,500 mm |
| Floor to indoor unit | 1,800 mm |
| Remote-controller range | Maximum 7 m |
Human sensor: Approximate detection range is 7 m, 90° vertically and 100° horizontally. Keep heaters and large objects outside the detection area.
Six piping directions
Right rear Right Right bottom Left bottom Left Left rear
| 1 | Select a strong, level wall with unrestricted airflow, suitable drainage and adequate service access. |
| 2 | Secure the wall-hook bracket horizontally and vertically using at least five large 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 | For left-side routes, transfer the drain hose and drain cap and refit the retaining screw. |
| 6 | Keep the drain hose below the refrigerant pipes and maintain continuous fall. |
| 7 | Engage the upper hooks first, then push the lower fittings onto the bottom hooks. |
Drainage: Do not lift the drain hose, create waves or submerge its end. Apply freeze protection where the drain hose may be exposed below 0°C.
3. Outdoor-unit installation
| Obstacle arrangement | Minimum clearance |
|---|---|
| Rear only | 100 mm |
| Rear and both sides | Rear 100 mm; sides 100 mm and 250 mm |
| Front only | 600 mm |
| Front and rear | Front 600 mm; rear 100 mm |
| Rear and overhead obstruction | Rear 100 mm; overhead 600 mm; obstruction depth maximum 200 mm |
| Multiple units side by side | Minimum 250 mm between units |
- Mount on a secure base at least 50 mm wide using four M10 anchor bolts.
- Anchor-bolt projection should be approximately 20 mm.
- Do not tilt the outdoor unit more than 3° or towards the compressor side.
- Do not install directly on the ground.
- Raise the unit and provide snow protection in freezing or heavy-snow areas.
- Do not stack units where drainage from the upper unit can freeze onto the lower unit.
4. Flare connections
| Pipe size | Torque |
|---|---|
| 6.35 mm | 16–18 N·m |
| 12.70 mm | 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. Apply alkylbenzene oil to the outdoor flare surface; do not use mineral oil.
5. Nitrogen sealing test
Dry nitrogen only. Never use oxygen, compressed air, refrigerant or flammable gas for the sealing test.
| 1 | Confirm both service valves are closed and power remains isolated. |
| 2 | Introduce dry nitrogen to both liquid and gas lines. |
| 3 | Pressurise the system to 4.15 MPa. |
| 4 | Leak-test all flare connections and brazed joints. |
| 5 | Allow the system to stand for 24 hours and confirm pressure has not fallen. |
| 6 | Allow for ambient-temperature change: approximately 0.05 MPa per 5°C. |
6. Vacuum and additional charging
- Connect a clean R32/R410A manifold and vacuum pump to the charging port.
- Evacuate to -0.1 MPa / -76 cmHg and confirm the vacuum target specified by the service equipment.
- Continue operating the vacuum pump for at least 15 minutes after reaching target vacuum.
- Close the manifold, stop the pump and confirm the vacuum holds.
- Fully open both service valves and tighten all caps.
- For pipework above 15 m, charge liquid R32 by electronic scale at 20 g/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 |
|---|---|
| M4 indoor terminal | 1.2–1.8 N·m |
Route the demand-control signal cable away from the power-supply and interconnection cables to prevent electrical 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. End the test using the remote-controller START/STOP button.
| 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 | ☐ |
| Additional refrigerant charge recorded | ☐ |
| Customer shown operation and filter maintenance | ☐ |
9. Optional controls
| Option | Reference |
|---|---|
| Two-wire wired remote controller | UTY-RNR series; communication kit UTY-TWRXZ2 required |
| Simple remote controller | UTY-RSR / UTY-RHR series; communication kit required |
| External input/output PCB | UTY-XCSXZ2 |
| External connect kit | UTY-XWZXZ5 |
| Communication kit | UTY-TWRXZ2 |
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. 9387603026-05 and outdoor installation manual Part No. 9319205274-04. This simplified field reference does not replace the complete manuals, equipment rating labels or current Australian and New Zealand regulations.