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ARTG09/12LLLB - AOTG09/12LBCA Single Phase Slim Duct R410A Units

Freshdesk Solution Article - Technical Support Step-by-Step Phone Instructions
Safety position: This guide is for technical support coaching of licensed and competent service personnel only. Before live testing, confirm the person onsite is authorised, has PPE and suitable test equipment. For power-off tests, isolate supply and wait before touching electrical components. Do not instruct a customer or unqualified person to remove covers or perform electrical tests.

1. Document scope

AreaDetails
Indoor modelsARTG09LLLB, ARTG12LLLB
Outdoor modelsAOTG09LBCA, AOTG12LBCA
System typeR410A single phase inverter slim duct system.
Core electrical focusOutdoor L-N supply, reverse transfer signal at terminal 1-3, forward transfer signal at terminal 2-3, CN14 remote supply check.
PurposeProvide a Freshdesk-ready call guide with linked flowcharts, component tests, expected readings and ticket evidence requirements.

2. Error code quick reference

CodeManual fault descriptionPhone support action / linked test
E:11Serial communication errorE:11 communication split flow
E:12Wired remote controller communication error3 wire remote controller check
E:32Indoor unit model information error / EEPROM access abnormalEEPROM / controller PCB
E:35Manual auto switch errorManual auto switch
E:41Indoor room thermistor errorThermistor testing
E:42Indoor heat exchanger thermistor errorThermistor testing
E:51Indoor unit fan motor errorIndoor fan motor
E:53Drain pump errorDrain / float switch
E:64PFC circuit errorPFC circuit flow
E:65Trip terminal L errorTrip terminal L flow
E:71Discharge thermistor errorOutdoor thermistor testing
E:73Heat exchanger liquid outlet thermistor errorOutdoor thermistor testing
E:74Outdoor thermistor errorOutdoor thermistor testing
E:84Current sensor errorCurrent sensor / main PCB
E:94Trip detectionTrip detection / overcurrent flow
E:95Compressor control errorCompressor control flow
E:97Outdoor unit fan motor errorOutdoor fan motor
E:994-way valve error4-way valve
E:A1Discharge temperature errorDischarge temperature flow

3. Quick map

Symptom / error familyMost likely areaJump to
No operation / remote blankSingle phase supply, indoor PCB remote supply, Y1/Y2/Y3 wiringRemote check
E:11Indoor/outdoor serial communication: reverse AC90-270 V at 1-3, forward AC30-130 V at 2-3Communication split flow
E:12 / remote commsY1/Y2/Y3 signal and indoor PCB CN14 remote supply3 wire remote flow
E:41/E:42/E:71/E:73/E:74Thermistor connector, resistance and PCB 5 V supplyThermistors
E:51/E:97Fan rotation, obstruction, motor short, PCB output voltageIndoor fan / Outdoor fan
E:64/E:65/E:94PFC / trip terminal L / overcurrent protectionE:64 / E:65 / E:94
E:95Compressor motor control / compressor harness / main PCBCompressor flow
E:A13-way valve, EEV/strainer, fan/heat exchanger, thermistor, refrigerant chargeDischarge temp flow

4. GREAT-style linked flowcharts

E:11 communication split flow - ARTG09/12LLLB slim duct

E:11 serial communication error or no indoor / outdoor communication
↓
↓
↓
Reverse transfer / outdoor signal path
Is AC90-270 V signal present at terminal 1-3?
YES
Outdoor reverse signal is present. Check field cable, noise, earthing and indoor receiving side.
NO
↓
If outdoor fan motor is abnormal, replace outdoor fan motor and main PCB. If fan motor is normal, main PCB becomes suspect.
Forward transfer / indoor signal path
Is AC30-130 V signal present at terminal 2-3?
YES
Indoor forward signal is present. Check wiring integrity, noise/earth and outdoor receiving side.
NO
Check indoor fan motor. If indoor fan is abnormal, replace indoor fan motor and controller PCB. If normal, controller PCB / outdoor main PCB sequence becomes suspect.
Useful linked checks
Important split: For ARTG09/12LLLB, reverse transfer is terminal 1-3 with AC90-270 V. Forward transfer is terminal 2-3 with AC30-130 V. Do not approve boards until supply, wiring, external noise/earthing and fan motor checks are documented.

3 wire remote controller communication check flow

Wired remote communication error / no operation / remote signal check
↓
↓
↓
Y1-Y3 is 12 VDC
no less than 11.4 VDC
Remote has controller power. Continue to Y2 signal checks.
Y1-Y3 is 0 VDC
Check CN14 terminal 1-3 on the indoor controller PCB. Manual reference is DC12 V supply to remote control.
Y1-Y3 below 11.4 VDC
Check cable length, poor joints, wrong polarity, damaged controller cable or loaded indoor PCB supply.
↓
Remove Y2 from the remote, keep conductor safe, then test between remote terminal Y2 and Y3
↓
Remote Y2-Y3 fluctuates 7-11 / 7-12 VDC pulse
Remote is producing signal. Continue to field cable signal check.
No pulse at remote Y2-Y3
Remote controller likely defective after confirming 12 VDC supply is correct.
↓
Test between disconnected Y2 wire going to indoor unit and Y3 COM
↓
Field Y2-Y3 fluctuates 7-11 / 7-12 VDC pulse
Indoor PCB is returning signal. Reconnect Y2. If communication still fails, inspect terminals, cable shielding/noise and controller condition.
No pulse on field Y2 wire
Check open cable / short to COM / incorrect terminal. If wiring is sound, suspect indoor controller PCB.
Record in ticket: Y1-Y3 supply voltage, remote Y2-Y3 pulse result, disconnected field Y2-to-Y3 pulse result, cable condition and CN14 1-3 voltage.

E:64 PFC circuit error flow - Outdoor unit

PFC circuit error / inverter output DC voltage higher than 415 V for over 3 seconds
↓
Check external cause at indoor and outdoor: voltage drop, momentary power failure, noise and grounding
↓
Check connector condition: removed connector, erroneous connection or open cable
↓
Reset power and confirm whether E:64 returns
↓
If checks do not improve symptom, main PCB becomes suspect
↓
External cause found
Correct supply/noise/earthing issue and retest before replacing parts.
Connector/wiring issue
Correct connector or wiring and reset power.
Fault remains
Replace main PCB after evidence is recorded.
Important: E:64 is supply/PFC sensitive. Record L-N voltage, grounding/noise check and connector condition before main PCB approval.

E:65 trip terminal L error flow - Outdoor unit

FO terminal of IPM is L = 0 V while the compressor stops
↓
Confirm error history and whether E:65 is repeatable after reset
↓
Check supply, earth and evidence of external noise or momentary power issue
↓
Inspect outdoor main PCB and compressor/inverter area for burn marks, loose terminals or water ingress
↓
If E:65 returns, replace outdoor main PCB as per manual sequence
↓
External cause found
Correct site supply/noise/earthing issue and retest.
Board damage / water ingress
Record photos and escalate board replacement decision.
Repeat E:65 confirmed
Outdoor main PCB replacement is the manual action.
Important: The slim duct manual lists E:65 as main PCB failure. Still record supply, earthing and visible board condition before approving the PCB.

E:94 trip detection flow - Outdoor unit

Overcurrent protection after inverter compressor start processing completed, generated consecutively 10 times
↓
Check outdoor fan operation, outdoor heat exchanger, air passages and ambient temperature
↓
Check whether discharged air is being sucked back into the outdoor unit
↓
If airflow/fan/ambient checks do not improve symptom, main PCB becomes suspect
↓
If main PCB does not improve symptom, compressor becomes suspect
↓
Airflow / heat exchanger issue
Clear obstruction, clean coil or correct recirculation before parts are replaced.
Main PCB suspected
Recommend main PCB only after airflow/fan evidence is documented.
Compressor suspected
Recommend compressor only after previous checks and main PCB sequence are completed.
Important: For E:94, prove outdoor airflow, fan operation, heat exchanger condition and ambient/recirculation before PCB or compressor recommendation.

E:95 compressor control error flow - Outdoor unit

Compressor rotor location out of phase protection repeated within 40 seconds
↓
Turn unit on and confirm whether abnormal compressor noise is present
↓
Isolate supply and visually inspect compressor harness cable, compressor terminals and main PCB connections
↓
Check compressor winding resistance U-V, V-W and U-W. Expected: 1.408 ohm ±8% at 25C
↓
If connection and winding checks are normal but the error remains, main PCB becomes suspect
↓
If main PCB does not improve symptom, compressor becomes suspect
↓
Abnormal compressor noise present
Record noise evidence and consider compressor fault after wiring and winding checks.
Harness burnt, loose, open or miswired
Repair or replace affected harness or terminal connection, then reset power and retest.
Compressor winding abnormal
Escalate as compressor fault after values are recorded.
All checks pass
Escalate main PCB first, then compressor if fault remains after PCB sequence.
Important: For E:95, physically inspect compressor harness and terminals. Do not replace compressor or PCB without recording compressor winding resistance and harness condition.

E:A1 discharge temperature error flow - Outdoor unit

Protection stop by discharge temperature 110C during compressor operation, generated twice within 24 hours
↓
Primary check: suspect refrigerant leak / insufficient refrigerant first
↓
Cooling: check 3-way valve gas side is open. Heating: check 3-way valve liquid side is open
↓
Check EEV opening, EEV coil resistance, strainer clogging and temperature difference across strainer
↓
Check outdoor fan operation and heat exchanger for foreign matter / blocked fins / recirculation
↓
Check discharge thermistor resistance and main PCB DC5.0 V supply
↓
Check refrigerant amount / leak test
↓
Leak or insufficient refrigerant found
Repair leak, pressure test, evacuate and weigh in charge as required.
3-way valve closed / not fully open
Open valve fully and re-test operation.
EEV / strainer issue
Confirm coil resistance, start-up noise, operation and temperature difference across restriction.
Discharge thermistor abnormal
Replace thermistor or repair harness only after value is confirmed against temperature.
All checks pass but fault remains
Main PCB becomes suspect after refrigerant, valves, EEV, airflow and thermistor are proven.
Important: Treat E:A1 as a refrigerant and system-condition fault first. Common causes are valve not opened, EEV/strainer issue, outdoor fan/heat exchanger issue, discharge thermistor fault, insufficient refrigerant or main PCB.

5. Step-by-step phone support SOPs

SOP 1 - Intake and safety gate

  1. Confirm caller name, company, site address, indoor model/serial and outdoor model/serial.
  2. Confirm exact complaint: error code, operating mode, when it occurs and whether it is repeatable.
  3. Confirm safety: no burning smell, water ingress, damaged wiring, repeated breaker trips or refrigerant odour.
  4. Confirm tools: multimeter with AC/DC volts, resistance and diode test.
  5. Decision point: if caller is not qualified or cannot identify terminals safely, stop at non-invasive checks and arrange authorised attendance.

SOP 2 - E:11 indoor/outdoor serial communication - slim duct

  1. Reset power and confirm if E:11 returns.
  2. Check external causes such as poor earth, noise or equipment causing harmonic wave near power cable.
  3. Check interconnect and control unit connections for loose connector, open cable or mis-wiring.
  4. Check outdoor supply: expected AC216-264 V at outdoor terminal L-N.
  5. Reverse transfer signal: check outdoor terminal 1-3. Expected swing AC90-270 V.
  6. Forward transfer signal: check outdoor terminal 2-3. Expected swing AC30-130 V.
  7. If reverse transfer signal is abnormal, check outdoor fan motor before outdoor main PCB approval.
  8. If forward transfer signal is abnormal, check indoor fan motor; if indoor fan is abnormal, replace indoor fan motor and controller PCB. If normal, controller PCB / outdoor main PCB sequence becomes suspect.

SOP 3 - 3 wire remote signal test

  1. At the rear of the wall controller, confirm Y1 = 12 V/red, Y2 = signal/white, Y3 = COM/black.
  2. Measure Y1 to Y3: expected 12 VDC, no less than 11.4 VDC.
  3. Manual PCB supply reference: CN14 terminal 1-3 is the power supply to remote control and should be approximately DC12 V.
  4. Remove Y2 from the remote. Measure between remote terminal Y2 and Y3: expected fluctuating 7-11 / 7-12 VDC pulse.
  5. Measure between the disconnected Y2 wire going to the indoor unit and Y3: expected fluctuating 7-11 / 7-12 VDC pulse.
  6. If no 12 V supply, check indoor PCB remote power supply. If remote has supply but no Y2 pulse, suspect remote controller. If field Y2 has no return pulse, check cable and indoor controller PCB.

SOP 4 - Thermistor testing

  1. Isolate power. Check connector is not loose, removed, miswired or open.
  2. Disconnect thermistor and measure resistance out of circuit. Compare to actual bulb temperature.
  3. Indoor room thermistor rough values: 0C 33.6 kΩ, 5C 25.9 kΩ, 10C 20.2 kΩ, 15C 15.8 kΩ, 20C 12.5 kΩ, 25C 10.0 kΩ, 30C 8.0 kΩ, 35C 6.5 kΩ, 40C 5.3 kΩ, 45C 4.3 kΩ.
  4. Indoor heat exchanger thermistor rough values: 0C 168.6 kΩ, 5C 129.8 kΩ, 10C 100.9 kΩ, 15C 79.1 kΩ, 20C 62.5 kΩ, 25C 49.8 kΩ, 30C 40.0 kΩ, 35C 32.4 kΩ, 40C 26.3 kΩ, 45C 21.6 kΩ, 50C 17.8 kΩ, 55C 14.8 kΩ, 60C 12.3 kΩ.
  5. Outdoor discharge thermistor rough values: 0C 168.6 kΩ, 25C 62.6 kΩ, 40C 26.3 kΩ, 60C 12.3 kΩ, 100C 3.4 kΩ, 120C 2.0 kΩ.
  6. Outdoor heat exchanger thermistor rough values: -10C 27.5 kΩ, 0C 16.1 kΩ, 10C 9.7 kΩ, 20C 6.1 kΩ, 40C 2.6 kΩ, 60C 1.3 kΩ.
  7. Outdoor temperature thermistor rough values: -20C 115.2 kΩ, -10C 62.3 kΩ, 0C 35.2 kΩ, 10C 20.7 kΩ, 20C 12.6 kΩ, 30C 8.0 kΩ, 50C 3.5 kΩ.
  8. With thermistor removed, check PCB supply at thermistor connector: expected DC5.0 V.

SOP 5 - Indoor fan motor testing

  1. Power off. Rotate fan by hand and check for obstruction, bearing lock, dropped fan or casing contact.
  2. Check ambient temperature around the motor and confirm no external heat source is affecting it.
  3. Check indoor fan motor using circuit-test between Vm and GND. If short-circuited below 300 kΩ, replace indoor fan motor and controller PCB.
  4. Indoor fan motor pin functions: Brown FG, Yellow Vsp, White Vcc, Black GND, Red Vm.
  5. Record fan rotation, motor reading, connector condition and PCB decision.

SOP 6 - Outdoor fan motor testing

  1. Power off. Rotate fan by hand and check obstruction, bearing lock, fan guard contact or damaged fan.
  2. Check ambient temperature around the motor and confirm no external heat source is affecting it.
  3. Check outdoor fan motor using circuit-test between Vm and GND. If short-circuited below 300 kΩ, replace outdoor fan motor and main PCB.
  4. Outdoor fan motor pin functions: Red Vm, Black GND, White Vcc, Yellow Vsp, Brown FG.
  5. Live output reference at PCB side connector: Red-Black 240-400 VDC; White-Black 15 VDC ±1.5 V.

SOP 7 - EEV and strainer testing

  1. Check EEV connector CN40 for loose connector or open cable.
  2. Remove connector and check EEV coil resistance: Yellow-Red, Orange-Red, Blue-Red and White-Red = 46 Ω ±4 Ω at 20C.
  3. Remove connector and check PCB drive voltage: expected DC12 V.
  4. Turn on power and listen/feel for EEV start-up operation noise.
  5. Check opening/closing effect by temperature difference. Closed valve creates inlet/outlet temperature difference; open valve has no temperature difference.
  6. Check strainer. A temperature difference across the strainer suggests internal clogging.

SOP 8 - Compressor testing

  1. Check compressor terminal connection and main PCB / transistor PCB connection for loose or incorrect wiring.
  2. Check winding resistance between U-V, V-W and U-W. Manual value: 1.408 Ω ±8% at 25C.
  3. If resistance is 0 or infinite, replace compressor.
  4. If compressor does not start or stops soon, also check gas pipe valve open, refrigerant leak, strainer clogging and harness condition before compressor approval.
  5. If connection and winding resistance do not improve symptom, main PCB becomes suspect as per manual sequence.

SOP 9 - PFC / main PCB

  1. Use this for E:64 PFC circuit error, E:65 trip terminal L and repeated inverter protection faults.
  2. Confirm L-N supply is within range before board approval.
  3. Inspect connectors and harnesses for loose connectors, corrosion, open cable or burn marks.
  4. Check compressor winding and outdoor fan motor loading before recommending main PCB where the manual sequence requires it.
  5. Attach photos and readings to ticket before board approval.

SOP 10 - Drain / float switch

  1. Check float switch operation and any blockage by dust.
  2. Remove float switch and check ON/OFF switching operation by meter.
  3. Check CN9 and shorted / pinched wire.
  4. Check drain hose for clogging, traps or poor fall.
  5. If all checks are normal and drainage error remains, controller PCB becomes suspect.

SOP 11 - Manual auto switch

  1. Check whether the manual auto switch is stuck or being held on.
  2. Check ON/OFF switching operation by meter.
  3. If manual auto switch is disabled, replace it.
  4. If switch testing does not improve symptom, replace controller PCB and indicator PCB as per manual.

SOP 12 - EEPROM / indoor model information

  1. Reset power and confirm if E:32 returns.
  2. Check all indoor electrical connectors for loose connector or incorrect wiring.
  3. Check PCB for shortage, corrosion or water damage.
  4. Check external cause such as poor earth or harmonic noise near the power cable.
  5. If checks do not improve symptom, replace controller PCB.

SOP 13 - Current sensor

  1. Reset power and confirm if E:84 returns.
  2. Check external causes: voltage drop, momentary open circuit, noise and grounding.
  3. Check outdoor electrical component connectors, terminal tightness, miswiring and open cables.
  4. If checks do not improve symptom, main PCB becomes suspect.

SOP 14 - 4-way valve

  1. Check connector is fitted, not miswired and no open cable.
  2. Check indoor thermistors are fitted in holders and not pinched or reading incorrectly.
  3. Remove CN30 and check solenoid coil resistance: approximately 1.4 kΩ.
  4. Check valve position by piping temperature difference. If valve position is not correct after coil and thermistors are proven, valve may be faulty.
  5. If checks pass and error remains, main PCB becomes suspect.

6. Ticket evidence checklist

Evidence requiredDetails to record
Model and serialIndoor and outdoor model/serial, controller type and exact error display.
Safety and site conditionWho is onsite, licence/competency confirmation, power isolation status, access limitations, water ingress/burning smell/short circuit risk.
Electrical readingsL-N supply voltage, reverse/forward communication readings, remote Y1/Y2/Y3 readings, fan motor Vm/GND result, PCB 5 V / 12 V checks.
Component readingsThermistor kΩ and measured temperature, EEV coil Ω, compressor winding Ω, PFC/main PCB observations.
Refrigeration evidenceValve positions, operating mode, ambient, fan operation, coil condition, pressures, leak test, strainer temperature difference, weighed charge details.
Approval decisionState what has been proven before recommending motor, thermistor, compressor, EEV, main PCB, controller PCB or indicator PCB.