Freshdesk paste note: paste this article in Freshdesk using the HTML/source-code view. This version uses inline formatting so navigation buttons and flowcharts keep spacing when Freshdesk strips embedded CSS.
ARTG45/54/60LDTA - AOTG45/54/60LBTA Single Phase R410A Ducted 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.
Document scopeError codesQuick mapFlowchartsE:11 communication3 wire remote checkE:64 active filterE:65 IPME:94 overcurrentE:95 compressor controlE:A1 discharge tempE:A5 low pressureRemote signal SOPIndoor fanOutdoor fanEEVThermistorsCompressorActive filterIPMTicket checklist
1. Document scope
| Area | Details |
|---|---|
| Indoor models | ARTG45LDTA, ARTG54LDTA, ARTG60LDTA |
| Outdoor models | AOTG45LBTA, AOTG54LBTA, AOTG60LBTA |
| System type | R410A single phase inverter ducted system. |
| Core electrical focus | Outdoor power and communication checks include outdoor L-N supply, reverse transfer signal at terminal 1-3, and forward transfer signal at terminal 2-3. |
| Purpose | Provide a Freshdesk-ready call guide with linked flowcharts, component tests, expected readings and ticket evidence requirements. |
2. Error code quick reference
| Code | Manual fault description | Phone support action / linked test |
|---|---|---|
| E:11 | Serial communication error | E:11 communication split flow |
| E:12 | Wired remote controller communication error | 3 wire remote controller check |
| E:15 | Automatic airflow adjustment error | Indoor fan / airflow adjustment |
| E:18 | External communication error | External I/O communication |
| E:23 | Combination error | Model combination check |
| E:26 | Indoor unit address setting error | Address / RC group check |
| E:29 | Connection unit number error | RC group connection check |
| E:32 | Indoor unit PCB model information error | PCB evidence and connector check |
| E:33 | Indoor unit motor electricity consumption detection error | Indoor fan motor / power PCB |
| E:39 | Indoor unit power supply error for fan motor | Fan motor power supply |
| E:3A | Indoor unit communication circuit error | Remote communication PCB |
| E:41 | Indoor room thermistor error | Thermistor testing |
| E:42 | Indoor heat exchanger thermistor error | Thermistor testing |
| E:51 | Indoor unit fan motor error | Indoor fan motor |
| E:53 | Drain pump error | Drain / float switch |
| E:5U | Indoor unit error | Intake and error confirmation |
| E:62 | Outdoor unit main PCB model information error | Outdoor PCB evidence |
| E:63 | Inverter error | Inverter / transistor PCB checks |
| E:64 | Active filter voltage error | Active filter flow |
| E:65 | IPM error | IPM error flow |
| E:71 | Discharge thermistor error | Outdoor thermistor testing |
| E:72 | Compressor thermistor error | Outdoor thermistor testing |
| E:73 | Heat exchanger liquid outlet thermistor error | Outdoor thermistor testing |
| E:74 | Outdoor thermistor error | Outdoor thermistor testing |
| E:77 | Heat sink thermistor error | Inverter / heat sink |
| E:84 | Current sensor error | Current sensor check |
| E:86 | Pressure sensor / high pressure switch error | Pressure sensor / high pressure switch |
| E:94 | Over current error | Over current flow |
| E:95 | Compressor control error | Compressor control flow |
| E:97 | Outdoor unit fan motor 1 error | Outdoor fan motor 1 |
| E:98 | Outdoor unit fan motor 2 error | Outdoor fan motor 2 |
| E:99 | 4-way valve error | 4-way valve |
| E:A1 | Discharge temperature error | Discharge temperature flow |
| E:A3 | Compressor temperature error | Compressor temperature / refrigerant flow |
| E:A5 | Low pressure error | Low pressure flow |
3. Quick map
| Symptom / error family | Most likely area | Jump to |
|---|---|---|
| No operation / remote blank | Single phase supply, indoor PCB remote supply, Y1/Y2/Y3 wiring | Remote check |
| E:11 | Indoor/outdoor serial communication: reverse AC90-270 V at 1-3, forward AC30-130 V at 2-3 | Communication split flow |
| E:12 / remote comms | Y1/Y2/Y3 signal and indoor PCB CN14 remote supply | 3 wire remote flow |
| E:41/E:42/E:71/E:72/E:73/E:74/E:77 | Thermistor connector, resistance and PCB 5 V supply | Thermistors |
| E:51/E:97/E:98 | Fan rotation, obstruction, motor short, PCB output voltage | Indoor fan / Outdoor fan |
| E:64/E:65/E:94 | Active filter / IPM / overcurrent protection | E:64 / E:65 / E:94 |
| E:95 | Compressor motor control / compressor harness / transistor PCB | Compressor flow |
| E:A1/E:A3 | 3-way valve, EEV/strainer, fan/heat exchanger, thermistor, refrigerant charge | Discharge/compressor temp flow |
| E:A5 | Low pressure, valve position, fan/heat exchanger, EEV/strainer, pressure sensor, refrigerant | Low pressure flow |
4. GREAT-style linked flowcharts
E:11 communication split flow - Single phase ARTG/AOTG LDTA/LBTA
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 signal is present. Check field cable, noise, earthing and indoor receiving side.
Forward transfer / indoor signal path
Is AC30-130 V signal present at terminal 2-3?
YES
Indoor signal is present. Check wiring integrity, noise/earth and outdoor receiving side.
NO
Indoor controller PCB becomes suspect only after wiring, supply and external-noise checks are proven.
Useful linked checks
Important split: For this single phase series, reverse transfer is checked at terminal 1-3 with AC90-270 V. Forward transfer is checked at terminal 2-3 with AC30-130 V. Do not approve boards until supply, wiring, external noise/earthing and component loading 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
no less than 11.4 VDC
Remote has controller power. Continue to Y2 signal checks.
Y1-Y3 is 0 VDC
Check CN14 on the indoor controller PCB terminal 1-3. Manual reference is DC13 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 active filter voltage error flow - Outdoor unit
Active filter voltage error: inverter input DC voltage high/low or momentary power cut on low voltage
↓
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
↓
Check active filter module
↓
Check transistor PCB / IPM
↓
If checks do not improve the 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.
Active filter abnormal
Replace active filter module after test result is recorded.
Transistor PCB abnormal
Replace transistor PCB after test result is recorded.
Important: E:64 is supply/inverter-link sensitive. Record L-N voltage, grounding/noise check, active filter result and transistor PCB result before main PCB approval.
E:65 IPM error flow - Outdoor unit
IPM error / inverter protection
↓
Confirm error history and whether the fault occurs on compressor start or after running
↓
Check single phase L-N supply and external causes: voltage drop, poor earth, noise or momentary power issue
↓
Check outdoor fan operation, heat exchanger condition and ambient recirculation
↓
Visually inspect compressor harness, transistor PCB connections and terminal condition
↓
Check compressor winding resistance U-V, V-W and U-W
↓
Check transistor PCB / IPM
↓
Supply/noise issue found
Correct supply, earthing or external noise issue and retest before replacing parts.
Airflow or fan fault
Correct airflow/coil/fan issue before PCB approval.
Compressor winding abnormal
Escalate as compressor fault after values are recorded.
IPM abnormal
Replace transistor PCB after IPM readings are recorded.
Important: E:65 should be treated as an IPM/inverter protection issue. Prove supply, fan/airflow, harness, compressor and transistor PCB before authorising boards.
E:94 over current error flow - Outdoor unit
Over current after inverter compressor start processing completed, repeated protection stop
↓
Check outdoor fan operation, outdoor heat exchanger, air passages and ambient temperature
↓
Check whether discharged air is being sucked back into the outdoor unit
↓
Inspect compressor harness and terminals for burning, overheating, loose connection or poor contact
↓
Check transistor PCB / IPM
↓
If checks do not improve the symptom, main PCB becomes suspect; if still unresolved, compressor becomes suspect
↓
Airflow / heat exchanger issue
Clear obstruction, clean coil or correct recirculation before parts are replaced.
Harness or connection fault
Repair harness/terminal. Do not fit PCB until connection integrity is restored.
IPM abnormal
Replace transistor PCB after readings are recorded.
Main PCB/compressor suspected
Follow manual sequence: main PCB first after checks, then compressor if symptom remains.
Important: For E:94, the manual checks airflow/heat exchanger/ambient first, then IPM, then main PCB and compressor. Do not jump straight to compressor or PCB without airflow and IPM evidence.
E:95 compressor control error flow - Outdoor unit
Compressor control error / compressor start or control protection
↓
Turn unit on and confirm whether abnormal compressor noise is present
↓
Isolate supply and visually inspect compressor harness cable, compressor terminals and transistor PCB connections
↓
Check compressor winding resistance U-V, V-W and U-W. Expected: 0.432 ohm at 20C for ARTG45LDTA; 0.24 ohm at 20C for ARTG54/60LDTA
↓
Check gas valve position, refrigerant leak, strainer clogging and compressor mechanical symptoms
↓
If compressor checks normal and fault remains, transistor PCB / main PCB sequence becomes suspect
↓
Abnormal compressor noise present
Record noise evidence and check compressor / harness before recommending compressor.
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 transistor PCB/main PCB after compressor and harness evidence is documented.
Important: For E:95, physically inspect compressor harness and terminals. Do not replace inverter parts without recording compressor winding resistance and harness condition.
E:A1 discharge temperature / E:A3 compressor temperature flow - Outdoor unit
Discharge or compressor temperature protection during compressor operation
↓
Primary check: suspect refrigerant leak / insufficient refrigerant first
↓
Check 3-way valve is fully open: gas side in cooling, liquid side in heating as applicable
↓
Check EEV operation / coil resistance, capillary / strainer restriction and temperature difference across strainer
↓
Check outdoor fan operation and heat exchanger for foreign matter / blocked fins / recirculation
↓
Check discharge or compressor temperature thermistor value and DC 5 V PCB supply
↓
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 / capillary / strainer issue
Confirm coil resistance, seating, operation noise and temperature difference across restriction.
Thermistor abnormal
Replace thermistor or repair harness only after value is confirmed against temperature.
All checks pass but fault remains
Main PCB/inverter control becomes suspect after refrigerant, valves, EEV, airflow and thermistor are proven.
Important: Treat E:A1/E:A3 as a refrigerant and system-condition fault first. The common causes are refrigerant leak, restriction, valves not fully open, fan/heat exchanger problems or thermistor error.
E:A5 low pressure error flow - Outdoor unit
Low pressure protection
↓
Check 3-way valve is fully open
↓
Check outdoor ambient and whether low pressure values are plausible
↓
Check outdoor fan operation, obstruction, recirculation and heat exchanger condition
↓
Check EEV operation and strainers for clogging
↓
Check pressure sensor characteristics and refrigerant amount
↓
Valve closed / restricted
Open valve fully, correct restriction and retest.
Ambient / airflow issue
Correct operating conditions, airflow, fan operation or blocked coil before replacing parts.
EEV / strainer issue
Check EEV coil, start-up noise, voltage and temperature difference across strainer.
Sensor issue
Confirm pressure sensor voltage/operation before PCB recommendation.
Refrigerant leak / undercharge
Repair leak, pressure test, evacuate and weigh in charge.
Important: Low pressure faults should be proven with valve position, airflow, EEV/strainer, sensor and refrigerant evidence before approving parts.
5. Step-by-step phone support SOPs
SOP 1 - Intake and safety gate
- Confirm caller name, company, site address, indoor model/serial and outdoor model/serial.
- Confirm exact complaint: error code, operating mode, when it occurs and whether it is repeatable.
- Confirm safety: no burning smell, water ingress, damaged wiring, repeated breaker trips or refrigerant odour.
- Confirm tools: multimeter with AC/DC volts, resistance and diode test.
- 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 - single phase
- Reset power and confirm if E:11 returns.
- Check external causes such as poor earth, noise or equipment causing harmonic wave near power cable.
- Check interconnect and control unit connections for loose connector, open cable or mis-wiring.
- Check outdoor supply: expected AC198-264 V at outdoor terminal L-N.
- Reverse transfer signal: check outdoor terminal 1-3. Expected swing AC90-270 V.
- Forward transfer signal: check outdoor terminal 2-3. Expected swing AC30-130 V.
- If reverse transfer signal is abnormal, check outdoor fan motor, active filter module, transistor PCB/IPM and filter PCB CN110 before outdoor main PCB approval.
- If forward transfer signal is abnormal, suspect indoor controller PCB after wiring and supply are proven.
SOP 3 - 3 wire remote signal test
- At the rear of the wall controller, confirm Y1 = 12 V/red, Y2 = signal/white, Y3 = COM/black.
- Measure Y1 to Y3: expected 12 VDC, no less than 11.4 VDC.
- Manual PCB supply reference: CN14 terminal 1-3 is the power supply to remote control and should be approximately DC13 V.
- Remove Y2 from the remote. Measure between remote terminal Y2 and Y3: expected fluctuating 7-11 / 7-12 VDC pulse.
- Measure between the disconnected Y2 wire going to the indoor unit and Y3: expected fluctuating 7-11 / 7-12 VDC pulse.
- 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
- Isolate power. Check connector is not loose, removed, miswired or open.
- Disconnect thermistor and measure resistance out of circuit. Compare to actual bulb temperature.
- 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 4.35 kΩ, 50C 3.59 kΩ.
- Indoor heat exchanger thermistor rough values: 0C 176 kΩ, 5C 134 kΩ, 10C 103 kΩ, 15C 80.3 kΩ, 20C 62.9 kΩ, 25C 49.7 kΩ, 30C 39.6 kΩ, 35C 31.7 kΩ, 40C 25.6 kΩ, 45C 20.8 kΩ, 50C 17.1 kΩ.
- With thermistor removed, check PCB supply at thermistor connector: expected DC5.0 V.
- Replace thermistor only when resistance is open/short/out of table. Replace PCB only when connector/wiring and thermistor are proven.
SOP 5 - Indoor fan motor testing
- Power off. Rotate fan by hand and check for obstruction, bearing lock, dropped fan or casing contact.
- Check ambient temperature around the motor and confirm no external heat source is affecting it.
- Check indoor fan motor using Service Parts Information: circuit-test between Vm and GND. If short-circuited below 300 kΩ, replace indoor fan motor and controller/power PCB as applicable.
- For E:33 or E:39, check connector condition and indoor power supply PCB before board replacement.
- Record fan rotation, motor reading, connector condition and PCB decision.
SOP 6 - Outdoor fan motor testing
- Power off. Rotate fan by hand and check obstruction, bearing lock, fan guard contact or damaged fan.
- Check ambient temperature around the motor and confirm no external heat source is affecting it.
- Check outdoor fan motor using circuit-test between Vm and GND. If short-circuited below 300 kΩ, replace outdoor fan motor and main PCB.
- Live output reference at PCB side connector: Red-Black 280-373 VDC; White-Black 15 VDC ±1.5 V.
- Outdoor fan motor pin functions: Red DC voltage Vm, Black GND, White Vcc, Yellow Vsp, Brown feedback FG.
SOP 7 - EEV and strainer testing
- Check EEV connector for loose connector or open cable.
- Remove connector and check EEV coil resistance: Red-Orange, Red-Yellow, Red-White, Red-Blue = 46 Ω ±4 Ω at 20C.
- Remove connector and check PCB drive voltage: expected DC12 V.
- Turn on power and listen/feel for EEV start-up operation noise.
- Check opening/closing effect by temperature difference. Closed valve creates inlet/outlet temperature difference; open valve has no temperature difference.
- Check strainer. A temperature difference across the strainer suggests internal clogging.
SOP 8 - Compressor testing
- Check compressor terminal connection and transistor PCB connection for loose or incorrect wiring.
- Check winding resistance between U-V, V-W and U-W. Manual value: ARTG45LDTA = 0.432 Ω at 20C; ARTG54/60LDTA = 0.24 Ω at 20C.
- If resistance is 0 or infinite, replace compressor.
- If compressor does not start or stops soon, also check gas pipe valve open, refrigerant leak, strainer clogging and harness condition before compressor approval.
- If Check Point 1 and 2 do not improve the symptom and compressor is normal, main PCB / transistor PCB sequence becomes suspect.
SOP 9 - Active filter module
- Use this for E:64 active filter voltage error, E:11 reverse transfer abnormal signal follow-on, and outdoor no-power style inverter-link faults.
- Check external causes first: voltage drop, momentary power failure, defective contact, noise and grounding.
- Check connector condition: removed connector, erroneous connection or open cable.
- Check active filter module using the service parts method. If abnormal, replace active filter module.
- If active filter is normal, continue to transistor PCB / IPM and then main PCB.
SOP 10 - Transistor PCB / IPM
- Use this for E:63 inverter error, E:64 active filter voltage error, E:65 IPM error and E:94 overcurrent.
- Confirm L-N supply is within range before board approval.
- Inspect transistor PCB connections and harnesses for loose connectors, corrosion, open cable or burn marks.
- Check compressor winding and outdoor fan motor loading before recommending transistor PCB.
- Attach photos and readings to ticket before board approval.
SOP 11 - Pressure sensor / high pressure / low pressure
- Check pressure sensor connector and wiring condition.
- Compare live pressure to sensor values when available from outdoor display mode.
- For A5, check valve position, ambient, outdoor fan, EEV/strainer and refrigerant amount before sensor or PCB replacement.
- Record actual pressure, operating mode, pipe temperatures, sensor reading and refrigerant evidence.
SOP 12 - Drain / float switch
- Check float switch operation and any blockage by dust.
- Remove float switch and check ON/OFF switching operation by meter.
- Check CN9 connector and shorted / pinched wire.
- Check drain hose for clogging, traps or poor fall.
- If all checks are normal and drainage error remains, controller PCB becomes suspect.
SOP 13 - Address / model combination / RC group setup
- Check model combination: indoor and outdoor unit must be correct for the system.
- Check RC group wiring and remote address setting.
- Check for mixed automatic and manual address settings in one RC group.
- Check duplicated remote controller address in one RC group.
- Correct settings, reset power and retest before controller PCB or main PCB approval.
SOP 14 - External I/O communication
- Check connection between controller PCB and external I/O PCB.
- Check connector condition on external I/O PCB and controller PCB: loose connector, open cable or mis-wiring.
- If connection is normal and fault remains, replace external I/O PCB first.
- If condition does not change after external I/O PCB, replace controller PCB.
SOP 15 - 4-way valve
- Check connector is fitted, not miswired and no open cable.
- Check relevant thermistors are fitted in holders and not pinched or reading incorrectly.
- Check solenoid coil / valve operation where accessible.
- Check valve position by piping temperature difference. If valve position is not correct after coil and thermistors are proven, valve may be faulty.
- If checks pass and error remains, board control becomes suspect.
SOP 16 - Current sensor
- Reset power and confirm if current sensor error returns.
- Check external causes: voltage drop, momentary open circuit, noise and grounding.
- Check outdoor electrical component connectors, terminal tightness, miswiring and open cables.
- If checks do not improve symptom, board-level fault becomes suspect.
6. Ticket evidence checklist
| Evidence required | Details to record |
|---|---|
| Model and serial | Indoor and outdoor model/serial, controller type and exact error display. |
| Safety and site condition | Who is onsite, licence/competency confirmation, power isolation status, access limitations, water ingress/burning smell/short circuit risk. |
| Electrical readings | L-N supply voltage, reverse/forward communication readings, remote Y1/Y2/Y3 readings, fan motor Vm/GND result, PCB 5 V / 12 V / 13 V checks. |
| Component readings | Thermistor kΩ and measured temperature, EEV coil Ω, compressor winding Ω, transistor PCB/IPM observations, active filter result. |
| Refrigeration evidence | Valve positions, operating mode, ambient, fan operation, coil condition, pressures, leak test, strainer temperature difference, weighed charge details. |
| Approval decision | State what has been proven before recommending motor, thermistor, compressor, active filter, transistor PCB/IPM, main PCB, controller PCB or power PCB. |