• Installation, commissioning, and service work must be completed by appropriately qualified personnel, in accordance with local electrical and refrigeration regulations.
• Isolate electrical supply before opening covers or touching terminals. Confirm safe isolation with an approved meter.
• Use correct lifting techniques and ensure outdoor unit is securely mounted on an adequate foundation.
• Do not bypass protective devices. Restore all covers and strain reliefs before energising.
• Leak testing and charging must be performed using correct refrigerant handling practices and recovery equipment.

• R32 is an A2L refrigerant (mildly flammable). Keep away from ignition sources. Do not use open flame near refrigerant.
• Provide adequate ventilation during installation and service. Use a suitable leak detector rated for A2L/R32.
• Use only specified components and service equipment compatible with R32 (and rated for the relevant pressures).
• When charging, use electronic scales and charge by weight. Avoid air ingress; use proper evacuation practices.
• After completing work, check for refrigerant leaks at flare joints and service ports using appropriate methods.

• Vacuum pump (deep vacuum capable) + vacuum-rated hoses
• Micron gauge / vacuum gauge (recommended for verification)
• Nitrogen cylinder + regulator (for pressure testing / purge)
• Electronic refrigerant scales (charging by weight)
• R32-compatible manifold / service tools (pressure rating suitable)
• Leak detector suitable for A2L/R32
• Flaring tool suitable for R410A/R32 flares + correct flare nuts
• Torque wrench and spanners for flare connections
• Insulation, UV-resistant cable ties, wall sleeve / putty / sealant, drain hose materials

Power

• Mains supply is connected to the outdoor unit.
• Indoor unit is powered/controlled via the interconnecting wiring from the outdoor unit (refer to wiring diagram / terminal markings).

Control & communication

• Indoor and outdoor units communicate via the interconnect wiring. Correct polarity, terminations, and tightness are essential.
• Optional wired remote controller (if fitted) can display error codes and supports function settings.

Commissioning flow

1. Install indoor and outdoor units; complete drain and interconnect wiring.
2. Connect and insulate refrigerant piping; complete flare joints to the correct standard.
3. Pressure test (nitrogen), leak check, then evacuate (deep vacuum).
4. Open service valves; charge additional refrigerant by weight if required.
5. Perform test run; verify stable operation; complete handover.

Connection pipe sizes (all models listed in this document)

• Liquid line: 6.35 mm (1/4 inch)
• Gas line: 9.52 mm (3/8 inch)

Allowable piping length and height

• Pre-charge length: 15 m
• Maximum total piping length: 20 m
• Maximum height difference: 15 m

Good practice for flare joints

• Cut pipe square and de-burr; prevent debris entering pipe (cap ends).
• Use correct flare nuts and flare dimensions suited for R32/R410A systems.
• Tighten flare joints to the correct torque using a torque wrench (avoid over-tightening).
• Insulate both liquid and gas lines where required to prevent condensation and efficiency loss.

Outdoor unit supply (all listed models)

• Rated voltage: 220–240 V~ 50 Hz
• Allowable voltage range: 198–264 V
• Minimum circuit: dedicated supply recommended
• Recommended breaker: 15 A
• Earth leakage circuit breaker (ELCB/RCD): 30 mA
• Supply cable: 1.5 mm²

Interconnect wiring

• Verify terminal markings match indoor and outdoor (polarity and terminal numbering).
• Confirm conductor retention (tug test), correct insulation stripping, and no strands protruding.
• Route wiring to avoid sharp edges and hot surfaces; reinstate cable clamps and grommets.

• Install on a level, rigid base with adequate drainage and anti-vibration provisions.
• Maintain airflow clearances around the outdoor unit; avoid recirculation and strong wind exposure where possible.
• Ensure the unit is anchored correctly. Do not install in locations where discharge air can short-circuit back to intake.
• Where snow/ice conditions apply, consider raising the unit and protecting from snow accumulation.

• Confirm wall strength and mounting plate level; allow space for service access.
• Wall hole: sleeve and seal to prevent ingress; ensure drain has continuous fall to discharge point.
• Drain: avoid traps and upward runs; confirm drain test with water before finalising.
• Route refrigerant lines with minimal bends; protect against kinks and mechanical damage.

Pressure test (nitrogen)

• After completing refrigerant piping, pressure test using dry nitrogen.
• Pressurise to 4.15 MPa and apply to both liquid and gas sides as per standard practice.
• Check all joints and service ports for leakage. If leak found: recover/vent nitrogen safely, repair, and re-test.

Evacuation

• After leak-free pressure test, evacuate the system using a vacuum pump (deep vacuum recommended).
• Confirm vacuum holds (no rise). If vacuum rises: investigate leaks or moisture contamination and rectify.

Commissioning

• Open service valves fully (liquid then gas as applicable) after evacuation and confirming stability.
• Verify supply voltage, current draw, and stable operation in cooling and heating modes (as applicable).
• Confirm condensate drainage and correct airflow (filters installed, louvers operating).

Base (factory) refrigerant charge by outdoor model

• AOTH07KNCA — 550 g (R32)
• AOTH09KNCA — 590 g (R32)
• AOTH12KNCA — 700 g (R32)
• AOTH14KNCA — 850 g (R32)

Additional charge calculation (based on total piping length)

• Piping length ≤ 15 m: no additional charge
• Piping length > 15 m: add 20 g per metre over 15 m, up to 20 m maximum

Examples

• 16 m total length → (16 − 15) × 20 = 20 g additional
• 18 m total length → (18 − 15) × 20 = 60 g additional
• 20 m total length → (20 − 15) × 20 = 100 g additional

Function settings are used to tailor indoor unit behaviour (filter reminder, temperature compensation, auto restart, external input/output behaviour, etc.). Record any changes as part of commissioning.

General process (high level)

• Enter function setting mode on the controller interface (wired remote if fitted) and select Function number and Setting value.
• Confirm the setting is stored, then return controller to normal operation.
• After changes, perform a test run to confirm behaviour is as expected.

11 – Filter sign

• 00 — Standard (400 hours)
• 01 — Long interval (1000 hours)
• 02 — Short interval (200 hours)
• 03 — No indication

30 – Room temperature control for indoor unit sensor (cooling)

• 00 — Standard
• 01 — No correction 0.0
• 02 — -0.5
• 03 — -1.0
• 04 — -1.5
• 05 — -2.0
• 06 — -2.5
• 07 — -3.0
• 08 — -3.5
• 09 — +0.5
• 10 — +1.0
• 11 — +1.5
• 12 — +2.0
• 13 — +2.5
• 14 — +3.0
• 15 — +3.5
• 17 — +4.0

31 – Room temperature control for indoor unit sensor (heating)

• 00 — Standard
• 01 — No correction 0.0
• 02 — -0.5
• 03 — -1.0
• 04 — -1.5
• 05 — -2.0
• 06 — -2.5
• 07 — -3.0
• 08 — -3.5
• 09 — +0.5
• 10 — +1.0
• 11 — +1.5
• 12 — +2.0
• 13 — +2.5
• 14 — +3.0
• 15 — +3.5
• 17 — +4.0

35 – Room temperature control for wired remote controller sensor (cooling)

• 00 — Standard
• 01 — No correction 0.0
• 02 — -0.5
• 03 — -1.0
• 04 — -1.5
• 05 — -2.0
• 06 — -2.5
• 07 — -3.0
• 08 — -3.5
• 09 — +0.5
• 10 — +1.0
• 11 — +1.5
• 12 — +2.0
• 13 — +2.5
• 14 — +3.0
• 15 — +3.5
• 17 — +4.0

36 – Room temperature control for wired remote controller sensor (heating)

• 00 — Standard
• 01 — No correction 0.0
• 02 — -0.5
• 03 — -1.0
• 04 — -1.5
• 05 — -2.0
• 06 — -2.5
• 07 — -3.0
• 08 — -3.5
• 09 — +0.5
• 10 — +1.0
• 11 — +1.5
• 12 — +2.0
• 13 — +2.5
• 14 — +3.0
• 15 — +3.5
• 17 — +4.0

40 – Auto restart

• 00 — Enable
• 01 — Disable

42 – Room temperature sensor switching (wired remote controller)

• 00 — Indoor unit
• 01 — Both

44 – Remote controller custom code

• 00 — A
• 01 — B
• 02 — C
• 03 — D

46 – External input control

• 00 — Operation/Stop mode 1 (for standard)
• 01 — Prohibited
• 02 — Forced stop mode
• 03 — Operation/Stop mode 2

48 – Room temperature sensor switching (Aux.)

• 00 — Both (for standard)
• 01 — Wired remote controller

49 – Indoor unit fan control for energy saving for cooling

• 00 — Disable
• 01 — Enable (for standard)
• 02 — Remote controller

60 – Switching functions for external output terminal

• 00 — Operation status
• 09 — Error status
• 10 — Indoor unit fan operation status

Test run

• Perform an operational test in cooling and heating (where ambient conditions permit).
• Confirm indoor fan speeds, louvers, temperature response, and outdoor fan/compressor start.
• Check for abnormal noise/vibration and confirm condensate drain performance.
• Confirm no fault codes present at completion.

Handover

• Demonstrate basic operation (mode selection, setpoint, fan speed, swing).
• Explain filter cleaning and any configured special settings (e.g., filter sign interval).
• Provide customer with documentation and confirm warranty requirements (where applicable).

Pump down is used to collect refrigerant into the outdoor unit prior to piping disconnection. Ensure safe work practices and correct refrigerant handling procedures.

Pump down procedure (forced cooling)

1. Confirm both service valves are open and the system is able to run.
2. Start forced cooling operation (manual operation as per unit procedure).
3. Close the 2-way (liquid) valve fully.
4. Allow operation to continue until suction pressure drops and the refrigerant is collected (do not run excessively).
5. Close the 3-way (gas) valve fully and stop operation.
6. Isolate power and proceed with service work.

The list below consolidates error displays used for indoor unit indication (LED patterns) and the corresponding error codes (for wired remote controller where fitted). Each item is presented as a single line to improve AI retrieval accuracy.

• 11 — Serial communication error (Indoor unit) | LEDs: OP 1 / TIMER 1 / ECON 1
• 12 — Serial communication error (Outdoor unit) | LEDs: OP 1 / TIMER 1 / ECON 2
• 13 — Indoor unit & wired remote controller communication error (not connected / cable error) | LEDs: OP 1 / TIMER 1 / ECON 3
• 14 — Indoor unit & wired remote controller communication error (connection unit error) | LEDs: OP 1 / TIMER 1 / ECON 4
• 15 — Check run unfinished | LEDs: OP 1 / TIMER 1 / ECON 5
• 16 — Peripheral unit communication error | LEDs: OP 1 / TIMER 1 / ECON 6
• 17 — Connection unit number error | LEDs: OP 1 / TIMER 1 / ECON 7
• 18 — Serial communication error (Outdoor unit communication circuit) | LEDs: OP 1 / TIMER 1 / ECON 8
• 21 — Unit number error | LEDs: OP 1 / TIMER 2 / ECON 1
• 24 — Overcurrent protection | LEDs: OP 1 / TIMER 2 / ECON 4
• 26 — Discharge temperature error | LEDs: OP 1 / TIMER 2 / ECON 6
• 27 — Discharge temperature thermistor error | LEDs: OP 1 / TIMER 2 / ECON 7
• 29 — Outdoor unit thermistor error (heat exchanger / suction) | LEDs: OP 1 / TIMER 2 / ECON 9
• 31 — Outdoor unit thermistor error (discharge / compressor) | LEDs: OP 1 / TIMER 3 / ECON 1
• 35 — Outdoor unit thermistor error (outdoor temperature) | LEDs: OP 1 / TIMER 3 / ECON 5
• 39 — Outdoor unit thermistor error (pressure sensor) | LEDs: OP 1 / TIMER 3 / ECON 9
• 41 — Room temperature thermistor error | LEDs: OP 1 / TIMER 4 / ECON 1
• 42 — Indoor heat exchanger thermistor error | LEDs: OP 1 / TIMER 4 / ECON 2
• 44 — Indoor unit thermistor error | LEDs: OP 1 / TIMER 4 / ECON 4
• 45 — Indoor unit fan motor 1 error | LEDs: OP 1 / TIMER 4 / ECON 5
• 46 — Indoor unit fan motor 2 error | LEDs: OP 1 / TIMER 4 / ECON 6
• 47 — Indoor unit fan motor 3 error | LEDs: OP 1 / TIMER 4 / ECON 7
• 48 — Indoor unit fan motor 4 error | LEDs: OP 1 / TIMER 4 / ECON 8
• 51 — Outdoor unit fan motor 1 error | LEDs: OP 1 / TIMER 5 / ECON 1
• 53 — Drain pump error | LEDs: OP 1 / TIMER 5 / ECON 3
• 54 — Outdoor unit compressor error | LEDs: OP 1 / TIMER 5 / ECON 4
• 57 — Outdoor unit compressor protector trip | LEDs: OP 1 / TIMER 5 / ECON 7
• 59 — Outdoor unit compressor lock error | LEDs: OP 1 / TIMER 5 / ECON 9
• 61 — Outdoor unit compressor start error | LEDs: OP 1 / TIMER 6 / ECON 1
• 62 — Outdoor unit compressor stop error | LEDs: OP 1 / TIMER 6 / ECON 2
• 63 — IPM error | LEDs: OP 1 / TIMER 6 / ECON 3
• 64 — Overcurrent error | LEDs: OP 1 / TIMER 6 / ECON 4
• 65 — PFC error | LEDs: OP 1 / TIMER 6 / ECON 5
• 66 — Outdoor unit & wired remote controller communication error | LEDs: OP 1 / TIMER 6 / ECON 6
• 68 — Outdoor unit fan motor 2 error | LEDs: OP 1 / TIMER 6 / ECON 8
• 69 — Outdoor unit fan motor 3 error | LEDs: OP 1 / TIMER 6 / ECON 9
• 71 — Outdoor unit fan motor 4 error | LEDs: OP 1 / TIMER 7 / ECON 1
• 73 — Outdoor unit heat exchanger thermistor error | LEDs: OP 1 / TIMER 7 / ECON 3
• 74 — Outdoor unit suction thermistor error | LEDs: OP 1 / TIMER 7 / ECON 4
• 75 — Outdoor unit discharge thermistor error | LEDs: OP 1 / TIMER 7 / ECON 5
• 76 — Outdoor unit compressor thermistor error | LEDs: OP 1 / TIMER 7 / ECON 6
• 77 — Outdoor unit liquid temperature thermistor error | LEDs: OP 1 / TIMER 7 / ECON 7
• 78 — Outdoor unit 4-way valve thermistor error | LEDs: OP 1 / TIMER 7 / ECON 8
• 79 — Outdoor unit outdoor temperature thermistor error | LEDs: OP 1 / TIMER 7 / ECON 9
• 83 — High pressure error | LEDs: OP 1 / TIMER 8 / ECON 3
• 84 — Low pressure error | LEDs: OP 1 / TIMER 8 / ECON 4
• 85 — Outdoor unit pressure sensor error | LEDs: OP 1 / TIMER 8 / ECON 5
• 86 — High pressure switch error | LEDs: OP 1 / TIMER 8 / ECON 6
• 87 — Low pressure switch error | LEDs: OP 1 / TIMER 8 / ECON 7
• 88 — Outdoor unit current sensor error | LEDs: OP 1 / TIMER 8 / ECON 8
• 91 — Outdoor unit reverse rotation error | LEDs: OP 1 / TIMER 9 / ECON 1
• 92 — Outdoor unit disconnecting operation | LEDs: OP 1 / TIMER 9 / ECON 2
• 93 — Outdoor unit reverse phase error | LEDs: OP 1 / TIMER 9 / ECON 3
• 94 — Inverter error | LEDs: OP 1 / TIMER 9 / ECON 4
• 95 — Overheat error | LEDs: OP 1 / TIMER 9 / ECON 5
• 96 — Outdoor unit EEPROM error | LEDs: OP 1 / TIMER 9 / ECON 6
• 97 — Outdoor unit fan motor error | LEDs: OP 1 / TIMER 9 / ECON 7
• 98 — Outdoor unit current error | LEDs: OP 1 / TIMER 9 / ECON 8
• 99 — Outdoor unit rotation error | LEDs: OP 1 / TIMER 9 / ECON 9
• A0 — Outdoor unit PCB error | LEDs: OP 1 / TIMER 10 / ECON 0
• A1 — Outdoor unit operation error | LEDs: OP 1 / TIMER 10 / ECON 1
• A2 — Outdoor unit / system error | LEDs: OP 1 / TIMER 10 / ECON 2

How to check error memory (summary)

• After restoring power, start the air conditioner and allow it to enter normal operating state.
• Use the service check method (controller/service procedure) to display stored fault history.
• After confirming, clear history only in accordance with your service procedure and verify normal operation.

Principle: Confirm safe isolation, then verify wiring/connection integrity, then measure the component (resistance/voltage), then compare to expected characteristics.

A) Thermistors (sensor checks)

Thermistors are NTC type. Check for open circuit, short circuit, and correct resistance vs temperature trend.

• Discharge temperature thermistor: 0°C ≈ 168.60 kΩ; 25°C ≈ 49.84 kΩ; 50°C ≈ 17.79 kΩ
• Compressor temperature thermistor: 0°C ≈ 168.60 kΩ; 25°C ≈ 49.84 kΩ; 50°C ≈ 17.79 kΩ
• Outdoor temperature thermistor: 0°C ≈ 33.34 kΩ; 25°C ≈ 10.00 kΩ; 50°C ≈ 3.60 kΩ

B) Communication faults (E:11 / E:12 / E:18 / E:3A)

• Inspect terminals and interconnect wiring for polarity, tightness, and continuity.
• Reset power after correcting wiring; confirm error clears and stable operation.
• If wiring is correct and error persists: isolate whether controller, indoor PCB, or outdoor PCB is failing (swap-test where permitted by your procedure).

C) Fan motor faults (E:51 / E:97)

• Check for physical obstruction, blade damage, and bearing seizure.
• Confirm correct supply to motor from the PCB and secure connector seating.
• Replace the fan motor if the motor does not rotate correctly with confirmed supply and command.

D) High pressure switch (E:86)

• Confirm airflow through outdoor coil and fan operation.
• Check refrigerant circuit for overcharge, restriction, or non-condensables (use proper recovery/recharge practices).
• Test switch continuity/operation according to your service practice.

E) Inverter / IPM / PFC / overcurrent (E:63 / E:64 / E:65 / E:94 / E:95)

• Confirm supply voltage within range and stable; check for loose mains connections.
• Inspect for burnt components/odour on inverter PCB; check compressor for winding issues and insulation faults.
• Replace inverter PCB and/or compressor as indicated by the troubleshooting path and verified test results.