Perth's ActronAir fault code lookup
ActronAir fault codes decoded
293 codes covered — what each one means, the likely cause, and whether it's worth trying something yourself before booking. Compiled from ActronAir documentation.
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ActronAir is the trickiest brand to look up, because the same E-number means different things on different equipment — E9 alone has four meanings across their ranges. The tables below are split by controller and product family, so find your system first (the model number is on the outdoor unit's rating plate), then read the code in that section.
Before you scroll: exact meanings can vary between model series — treat this as a well-informed starting point, not a service manual for your specific unit. And if a code appears alongside burning smells, breaker trips or water pouring from the unit, skip the table: switch off and call 0434 951 341.
How to find your ActronAir fault code
1
Ducted with an LM7 / LM24 wall controller
- 1 Nothing to press — the controller displays “EXX” on its screen when a fault is stored.
- 2 Note the digits after the E. That's your code.
- 3 Some protections show as flashing icons rather than codes: COOL + LOW flashing for 30 seconds is anti-freeze protection, HEAT + HIGH flashing is overheat protection, and HEAT flashing every 8 seconds is a normal defrost cycle.
- 4 A flashing FILTER light is a run-hours reminder, not a fault — clean the return-air filter, then press ON/OFF to clear it.
2
Ducted with an LR7 / NEO controller
- 1 The fault code (E01 through E104) appears directly on the controller screen.
- 2 At power-up each controller briefly shows its ID — C-1 is the master, C-2 and C-3 are secondary.
- 3 E56 on a secondary controller means it has lost contact with the C-1 master.
3
QUE touchscreen — the code is hidden
- 1 The home screen only shows an icon: a Failure icon means a fault is stored, a Warning icon means something needs attention, and Filter Clean is just the filter reminder.
- 2 The actual E-number lives in Menu > Technical, which ActronAir reserves for service technicians.
- 3 Menu > Dashboards is safe to look at and shows live status of the major components.
4
Wall splits — read the unit, not the remote
- 1 The remote never shows fault codes. The code appears in the small display window on the indoor unit (e.g. E4, F3, P1, or EH03 / EC51 on R-32 models).
- 2 If the display is hidden, count the OPERATION lamp flashes and check the TIMER lamp: TIMER off = E-family (indoor), TIMER on = F-family (outdoor), TIMER flashing = P-family (protection).
- 3 “dF” means defrosting and “CL” means the Active Clean cycle is running — neither is a fault.
Worth knowing: ActronAir E-numbers are NOT universal — the same number means different things across their ranges. E9, for example, is a pressure or phase error on a Classic/ESP Digital system, a low-pressure trip on an Advance/Aires, a comms fault on a WC-02 controller, and a twin-system indoor fault on a Cascade wall split. Match your equipment family (check the model number on the outdoor unit's rating plate) to the right table below before acting on any code. ActronAir also warns that a fault may not display on the wall controller until it has occurred several times, so an intermittent problem can be running long before you see a code. Technical support: 1800 119 229.
ActronAir fault code tables
Try this first safe check before calling anyone Book a service needs a technician Switch off & call stop running the system
ESP Platinum ducted (CRV / ERV / ARV / FRV / ERM) — LM7, LM24 and LM-ZC wall controllers
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| E3 | Room temperature sensor fault (open or short circuit). | Failed room sensor in the wall controller or a zone sensor, or a damaged/loose sensor cable. | Book a service |
| E4 | Indoor coil inlet sensor fault (open or short circuit). | Failed coil-in thermistor on the indoor fan coil, or its plug has worked loose at the indoor board. | Book a service |
| E5 | Communication error between the outdoor and indoor units. | Damaged or loose control wiring between the units, water ingress at a junction, or a failed board. Often transient after a storm or power event. | Try this first Switch the system off at the wall controller, then turn off both the indoor and outdoor isolators/breakers for 2 minutes, restore power and restart. If E5 comes back, book a technician. |
| E6 | High discharge temperature — compressor discharge exceeded 138 °C. | Almost always low refrigerant charge (a leak), a restriction in the refrigerant circuit, or a badly blocked outdoor coil. | Switch off & call |
| E7 | Outdoor coil sensor fault (open or short circuit). | Failed or disconnected outdoor coil thermistor. Defrost control is unreliable while this is present. | Book a service |
| E8 | Outdoor discharge sensor fault (open or short circuit). | Failed or disconnected discharge-line thermistor on the compressor. | Book a service |
| E9 | Low pressure (LP) switch has tripped. | Loss of refrigerant, a blocked/iced indoor coil from a dirty return-air filter, or a stuck expansion device. | Book a service |
| E10 | Low pressure sensor fault (open or short circuit). | Failed LP transducer or its wiring loom in the outdoor unit. | Book a service |
| E11 | High pressure (HP) switch has tripped. | Restricted airflow across the outdoor coil — dirty coil, plants/debris/fence too close, recirculating hot air — or a failed condenser fan. | Try this first With the system off, clear leaves, grass clippings, plants and stored items from around and above the outdoor unit (allow clear space on all sides), gently hose loose debris off the outside of the coil fins, and clean the return-air filter. Then power cycle and restart. |
| E12 | High pressure sensor fault (open or short circuit). | Failed HP transducer or its wiring in the outdoor unit. | Book a service |
| E14 | Condenser pressure low. | Low refrigerant charge, or operation in very low ambient conditions with a fan/control fault. | Book a service |
| E15 | Communication error with the variable speed drive (VSD). | Loss of the internal data link between the outdoor control board and the inverter drive — loose plug, damaged loom, or failed drive. | Book a service |
| E17 | Peripherals error. | An outdoor board peripheral device has failed self-check. | Book a service |
| E18 | Suction temperature sensor in the EEV module is open circuit. | Failed or unplugged suction thermistor on the electronic expansion valve module. | Book a service |
| E19 | Suction temperature sensor in the EEV module is short circuit. | Damaged suction thermistor or a chafed sensor cable. | Book a service |
| E22 | Ambient temperature sensor failure (open/short circuit) — unit drops to Safe Mode. | Failed outdoor ambient thermistor. The unit keeps running on a fallback strategy with reduced efficiency. | Book a service |
| E23 | EEV board communication failure — unit drops to Safe Mode. | Loss of comms to the electronic expansion valve board; loose plug or failed board. | Book a service |
| E25 | Ambient temperature not updated. | The outdoor ambient reading has stopped refreshing — sensor or comms issue. | Book a service |
| E26 | Drive over current. | The inverter has drawn more current than allowed — compressor loading up, seized/stiff compressor, or drive fault. | Switch off & call |
| E27 | Drive over voltage. | Incoming mains voltage too high, or a drive/DC-bus fault. | Switch off & call |
| E28 | VSD temperature high. | The inverter drive is overheating — blocked outdoor airflow, failed drive cooling, or extreme ambient. | Try this first Switch off and clear anything restricting airflow to the outdoor unit (debris, plants, covers, stacked items). Let it cool for 30 minutes before restarting. If it returns, book a technician. |
| E29 | Low supply voltage to the drive. | Mains supply sagging, an undersized or damaged supply cable, or a loose electrical connection. | Switch off & call |
| E30 | Drive trip lock — the inverter has locked out after repeated trips. | A repeating underlying drive or compressor fault has latched the drive off. | Switch off & call |
| E31 | Drive internal error. | Internal self-check failure in the inverter drive. | Switch off & call |
| E32 / E33 | Envelope protection — HP/LP trip detected by the drive pressure sensors. | The compressor was pushed outside its safe pressure envelope; commonly airflow restriction (indoor filter or outdoor coil) or refrigerant charge issues. | Book a service |
| E34 | Derating — high VSD temperature. The unit reduces capacity to protect the drive. | Restricted outdoor airflow or very high ambient temperature. | Try this first Clear debris, plants and stored items from around the outdoor unit and make sure hot discharge air isn't recirculating back into it. This is a derate, not a shutdown — the system will still run, just at reduced capacity. |
| E35 | Derating — low suction pressure. | Restricted indoor airflow (dirty filter, too few zones open) or low refrigerant charge. | Try this first Clean the return-air filter and open more zones so the system has enough airflow. If the derate persists after a clean filter and 3+ zones open, book a technician. |
| E36 | Derating — low condenser pressure. | Very low ambient conditions or charge/control issue. | Book a service |
| E37 | Derating — high condenser pressure. | Dirty or obstructed outdoor coil, failed condenser fan, or extreme ambient heat. | Try this first With the unit off, gently hose loose dirt off the outside of the outdoor coil fins and clear at least 300 mm of space around the unit. |
| E38 | Derating — output power limit reached. | The drive is capping output to stay within safe limits. | Book a service |
| E39 | Defrosting timed out. | The outdoor coil did not clear ice within the allowed time — heavy icing, failed defrost sensor, or reversing valve issue. | Book a service |
| E40 | VSD restarting too frequently. | The drive is repeatedly stopping and restarting due to an underlying protection trip. | Book a service |
| E41 | DC link voltage low. | Supply problem or a failing DC bus / capacitor bank in the inverter drive. | Switch off & call |
ESP Platinum QUE ducted (CRQ / ERQ / ARV / FRQ) — QUE QT-1000 touchscreen (codes read in the Tech Menu)
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| E02 | Indoor coil IN sensor error (open or short circuit). | Failed coil-inlet thermistor on the indoor unit. | Book a service |
| E03 | Room sensor error (open or short circuit). | Failed wall-controller or zone temperature sensor, or a damaged sensor cable. | Book a service |
| E04 | Indoor coil sensor error (coil-out on 3-phase, coil-in on single phase). | Failed indoor coil thermistor or loose plug at the indoor board. | Book a service |
| E05 | Communication error between the outdoor unit and the indoor unit | Break in the RS485/comms pair between outdoor and indoor units, water in a junction, loose terminal, blown indoor 24 V supply, or a failed indoor/outdoor board. The outdoor board shows E05 while the QUE Tech Menu logs the same fault as E51 — a common source of confusion. | Book a service |
| E13 | VSD HSP connector jumper pin missing, or other drive error. | A jumper link on the drive has been left off after a service, or an unclassified inverter fault. | Book a service |
| E42 | Envelope protection — extremely low evaporating pressure. | Severe indoor airflow restriction (blocked filter, too few zones open, iced coil) or low refrigerant charge. | Book a service |
| E43 | Envelope protection — high compression ratio. | The compressor is being asked to work outside its safe pressure ratio; typically airflow or charge related. | Book a service |
| E44 | Envelope protection — high condensing pressure. | Blocked or dirty outdoor coil, failed condenser fan, or recirculating hot air. | Try this first Switch off and clear leaves, grass and obstructions from around the outdoor unit, then gently hose the outside of the coil fins. Restart after 5 minutes. |
| E45 | Envelope protection — low compression ratio. | Compressor operating outside its envelope, often with a valve or charge fault. | Book a service |
| E47 | Compressor torque limit error. | The compressor is drawing more torque than allowed — mechanical stiffness, liquid flood-back or a drive fault. | Switch off & call |
| E50 | Outdoor board configuration error. | The outdoor control board is set for the wrong model, or a firmware/parameter fault after a board replacement. | Book a service |
| E51 | Communication error between outdoor and indoor units. | Damaged or loose interconnect wiring, water in a junction, or a failed board. Often transient after a power event. | Try this first Turn the system off at the touchscreen, then off at both isolators/breakers for 2 minutes, restore power and restart. If E51 returns, book a technician. |
| E52 | Communication error between the indoor unit and the master (QUE) controller. | Loose or damaged controller cable, or the touchscreen has lost its data link. | Try this first Power cycle the system at the breaker for 2 minutes. If the touchscreen still won't talk to the unit, book a technician — don't unscrew the controller yourself. |
| E53 | Communication error between the indoor board and the zone (VAV / 8-zone) module. | Loose zone module cable or a failed zone module. | Book a service |
| E55 | Communication error between BMS and outdoor unit. | Building management / external control link lost — only applies where a BMS is connected. | Book a service |
| E56 | No master wall controller detected. | The C-1 master controller has lost power, been disconnected, or its cable has failed. | Try this first Power cycle at the breaker for 2 minutes. If the main controller screen is blank or the code stays, book a technician. |
| E99 | Envelope protection (general). | The compressor has been driven outside its safe operating envelope. | Book a service |
Advance & Aires ducted (CRV / EVV / EAA / EFV, CRS / EVA) and Classic 2 (CRA / CCA / EVA / EAA / EFA) — NEO, LR7-1 and LC7-2 controllers
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| E01 (or E1) | Indoor fan RPM feedback error — the indoor fan isn't running at the speed the board asked for. | Heavily blocked return-air filter or grille, most zones closed, a seized/failing indoor fan motor, or a fan control board fault. | Try this first Turn the system off, remove and clean (vacuum or wash and fully dry) the return-air filter, make sure the return-air grille isn't blocked by furniture, open several zones, then power cycle at the breaker for 2 minutes and restart. |
| E03 (or E3) | Indoor room temperature sensor error (open or short circuit). | Failed sensor in the wall controller or a zone sensor, or damaged sensor wiring. ActronAir's own FAQ describes E3 as a sensor fault. | Book a service |
| E04 (or E4) | Indoor coil IN temperature sensor error (open or short circuit). | Failed coil-inlet thermistor or a plug that has vibrated loose at the indoor board. | Book a service |
| E06 (or E6) | High discharge temperature — compressor discharge exceeded 117 °C. | Low refrigerant charge (leak), restriction in the refrigerant circuit, or severe condenser airflow restriction. | Switch off & call |
| E07 (or E7) | Outdoor coil temperature sensor error (open or short circuit). | Failed or disconnected outdoor coil thermistor — defrost control becomes unreliable. | Book a service |
| E08 (or E8) | Discharge temperature sensor error (open or short circuit). | Failed or disconnected compressor discharge thermistor. | Book a service |
| E09 (or E9) | Low pressure (LP) switch tripped. ActronAir's official FAQ describes E9 as a low-pressure fault. | Refrigerant loss, an iced-up indoor coil caused by a dirty filter or closed zones, or a stuck expansion valve. | Book a service |
| E10 | Low pressure sensor error (open or short circuit). | Failed LP transducer or damaged sensor loom in the outdoor unit. | Book a service |
| E11 | High pressure (HP) switch tripped. | Blocked or filthy outdoor coil, plants/debris around the unit, hot air recirculating, or a dead condenser fan. | Try this first Switch off, clear at least 300 mm around the outdoor unit (leaves, grass, plants, bins), gently hose loose debris off the outside of the coil fins, then restart. Note ActronAir documentation says HP/LP faults may not display until they've occurred several times. |
| E12 | High pressure sensor error (open or short circuit). | Failed HP transducer or its wiring. | Book a service |
| E13 | VSD HSP connector jumper pin missing (R-410A Uno board), or other drive errors. | Jumper link left off after service, or an unclassified inverter drive fault. | Book a service |
| E15 | Communication error between the outdoor unit and the variable speed drive (Modbus link lost). | Loose or damaged data cable between outdoor board and inverter, or a failed drive. | Book a service |
| E18 | Suction temperature sensor error (open/short circuit or abnormal reading). | Failed suction-line thermistor or a chafed sensor cable. | Book a service |
| E22 | Ambient temperature sensor error (open/short circuit). | Failed outdoor ambient thermistor; the unit runs on a fallback control strategy. | Book a service |
| E26 | Drive supply over current / compressor effective value over current. | Excessive current draw — stiff or failing compressor, or drive fault. | Switch off & call |
| E27 | Drive supply over voltage. | Mains voltage too high or a drive/DC-bus fault. | Switch off & call |
| E28 | Drive (IPM module) temperature high. | Inverter overheating — restricted outdoor airflow or failed drive cooling. | Try this first Switch off, clear anything restricting airflow around the outdoor unit and let it cool for 30 minutes before restarting. |
| E29 | Drive low supply voltage. | Sagging mains supply, undersized or damaged supply cable, or a loose terminal. | Switch off & call |
| E30 | Drive trip lock. | The inverter has latched off after repeated protection trips. | Switch off & call |
| E41 | DC link voltage low. | Supply fault or failing DC bus capacitors in the inverter. | Switch off & call |
| E42 | Envelope protection — extremely low evaporating pressure. | Severe indoor airflow restriction or low refrigerant charge. | Book a service |
| E43 | Envelope protection — high compression ratio. | Compressor working outside its safe pressure ratio. | Book a service |
| E44 | Envelope protection — high condensing pressure. | Dirty/blocked outdoor coil or failed condenser fan. | Try this first Switch off and clear debris and plants from around the outdoor unit, then gently hose the outside of the coil fins. |
| E45 | Envelope protection — low compression ratio. | Compressor operating outside its envelope; often a valve or charge fault. | Book a service |
| E47 | Compressor torque limit error. | Compressor drawing excessive torque — mechanical stiffness, liquid flood-back, or drive fault. | Switch off & call |
| E50 | Outdoor board configuration error. | Board configured for the wrong model or a parameter fault after board replacement. | Book a service |
| E51 | Communication error between the outdoor and indoor units. | Damaged or loose interconnecting control wiring, water ingress, or a failed board. Frequently transient after storms or power outages. | Try this first Switch off at the wall controller, then off at both isolators/breakers for 2 minutes, restore power and restart. If it returns, book a technician. |
| E52 | Communication error between the indoor unit and the wall controller. | Loose or damaged controller cable, or a failed controller. | Try this first Power cycle at the breaker for 2 minutes. If the controller screen stays blank or the code returns, book a technician. |
| E55 | Communication error between BMS and outdoor unit. | External building-management control link lost — only relevant where a BMS is fitted. | Book a service |
| E56 | No master wall controller detected. | The C-1 master LR7/NEO controller has lost power or its cable connection. Secondary controllers (C-2, C-3) will show this if the master is disconnected. | Try this first Power cycle at the breaker for 2 minutes and check whether the main controller lights up. If it stays dead, book a technician. |
Inverter drive (VSD) fault codes E60–E104 — Advance, Aires and QUE Platinum outdoor units
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| E60 | Compressor phase over current / instant over current. | Compressor drawing excessive current on one phase — winding, bearing or drive fault. | Switch off & call |
| E61 | Compressor loss of phase / output phase loss. | An open compressor winding or a broken drive output connection. | Switch off & call |
| E62 | DC bus over voltage. | Mains surge or a regenerative/braking fault in the drive. | Switch off & call |
| E63 | DC bus under voltage. | Supply dip, failing rectifier or capacitor bank. | Switch off & call |
| E64 | Compressor loss of rotor (or, on some models, voltage input over high). | The drive has lost track of the compressor rotor — stalled or seizing compressor. | Switch off & call |
| E65 | Compressor U-phase current sensor fault (or input phase loss). | Failed current sensor on the drive board, or a lost incoming supply phase. | Switch off & call |
| E66 | AC voltage imbalance / AC input loss of phase. | Unbalanced or missing incoming supply phase — a supply-side electrical problem. | Switch off & call |
| E67 | Inverter de-saturation (or compressor model configuration error). | IGBT de-saturation event in the drive — a hard electrical fault. | Switch off & call |
| E68 | Compressor V-phase current sensor fault. | Failed current sensing circuit on the drive board. | Switch off & call |
| E69 | PFC-IGBT over temperature. | Power factor correction stage overheating — restricted drive cooling or high load. | Book a service |
| E70 | Lost rotor position. | The drive can no longer determine compressor rotor position — stalling or a sensing fault. | Switch off & call |
| E71 | Motor temperature sensor / thermistor fault. | Failed compressor motor thermistor or its wiring. | Book a service |
| E72 | Pre-charge relay open. | The drive's soft-charge relay has failed to close — drive board fault. | Switch off & call |
| E73 | Compressor W-phase current sensor fault. | Failed current sensing circuit on the drive board. | Switch off & call |
| E74 | IGBT over current / PFC module over current (choke wiring or failure). | Short or over-current in the drive power stage or its choke wiring. | Switch off & call |
| E75 | Compressor phase current fold-back timeout. | The drive has been limiting current for too long — sustained overload. | Book a service |
| E76 | Power module temperature fold-back timeout. | The drive has been derating on temperature for too long — cooling restriction or high ambient. | Try this first Switch off and clear airflow obstructions around the outdoor unit, then let it cool 30 minutes before restarting. |
| E77 | AC input current fold-back timeout. | Prolonged supply-current limiting — supply or load problem. | Book a service |
| E78 | PFC-IGBT temperature low, or auto-config communication timeout. | Temperature sensing fault on the PFC stage, or a drive configuration handshake failure. | Book a service |
| E79 | IPM de-saturation protection / compressor hardware over current. | Severe over-current event in the inverter power module. | Switch off & call |
| E80 | Motor temperature high. | Compressor motor running hot — overload, low charge, or restricted airflow. | Switch off & call |
| E81 | Drive board temperature high. | Drive electronics overheating. | Book a service |
| E82 | Power module temperature high. | Inverter power module overheating — cooling restriction or extreme ambient. | Try this first Switch off and clear anything blocking airflow around the outdoor unit; let it cool before restarting. |
| E83 | PFC-IGBT temperature high. | Power factor correction stage overheating. | Book a service |
| E84 | Internal drive communication lost between DSP and PFC. | Internal drive data link failure. | Book a service |
| E85 | Internal drive communication lost between comms processor and DSP. | Internal drive data link failure. | Book a service |
| E86 | Compressor phase current imbalance. | Uneven current across compressor windings — a failing compressor or drive output stage. | Switch off & call |
| E87 | Three-phase PFC current imbalance. | Unbalanced supply or a fault in the PFC stage. | Switch off & call |
| E88 | Drive micro-electronic or EEPROM fault. | Corrupted drive memory or a failed microcontroller. | Book a service |
| E89 | Motor over speed. | Compressor running beyond its commanded speed — control or sensing fault. | Switch off & call |
| E90 | Compressor model configuration error (or non-synchronism protection). | Drive configured for the wrong compressor after a board or compressor replacement. | Book a service |
| E91 | Inverter temperature imbalance. | Uneven temperature across the inverter power module — sensing or cooling fault. | Book a service |
| E92 | PFC temperature imbalance. | Uneven temperature across the PFC stage. | Book a service |
| E93 | Motor temperature low. | Compressor motor thermistor reading implausibly low — sensing fault. | Book a service |
| E94 | Drive board temperature low. | Board temperature sensing fault, or genuine extreme cold. | Book a service |
| E95 | Power module temperature low or sensor open circuit. | Failed temperature sensing circuit on the inverter power module. | Book a service |
| E96 | PFC-IGBT temperature low or PFC temperature sensing circuit fault. | Failed temperature sensing on the PFC stage. | Book a service |
| E97 | Comms ADC failure / drive IC reset malfunction. | Analog-to-digital converter or processor reset fault inside the drive. | Book a service |
| E98 | PFC / input current sensor fault. | Failed current sensing circuit on the drive. | Switch off & call |
| E99 | Compressor overload (or other drive malfunction). | The compressor has been driven beyond its rated load. | Switch off & call |
| E100 | PFC hardware over current / drive charging circuit malfunction. | Hard over-current event or a failed soft-charge circuit in the drive. | Switch off & call |
| E101 | PFC software over current / PFC module instant over current. | Over-current detected in the power factor correction stage. | Switch off & call |
| E102 | PFC over voltage (or, on Aires/19 kW+ models, DC fan motor 1 malfunction). | Over-voltage in the PFC stage, or a failed outdoor DC fan motor depending on model. | Switch off & call |
| E103 | Power module temperature low / sensor open fault (or DC fan motor 2 malfunction). | Temperature sensing fault on the power module, or a failed second outdoor fan motor depending on model. | Book a service |
| E104 | Drive fault limit lockout (or compressor model error). | The drive has locked out after exceeding its allowed number of faults. | Switch off & call |
Classic ducted (SRE / SRA / SRG) and ESP Digital ducted (SRD / SRV) — LM7 and LM24 wall controllers
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| E2 | Indoor coil-out sensor fault (open or short circuit). ESP Digital SRD/SRV only. | Failed coil-outlet thermistor or a loose plug at the indoor board. | Book a service |
| E3 | Room sensor(s) fault (open or short circuit). | Failed wall-controller or zone temperature sensor, or damaged sensor cable. | Book a service |
| E4 | Indoor coil-in sensor fault (open or short circuit). | Failed coil-inlet thermistor or loose connection. | Book a service |
| E5 | Communication error between the outdoor and indoor units. | Loose or damaged control wiring between units, water in a junction, or a board fault. Often transient after a power event. | Try this first Turn the system off, switch off both indoor and outdoor isolators/breakers for 2 minutes, restore power and restart. If E5 returns, book a technician. |
| E6 | Discharge high temperature fault — ActronAir's own documentation notes this usually means the system is low on refrigerant. | Refrigerant leak, restriction in the refrigerant circuit, or badly blocked condenser airflow. | Switch off & call |
| E7 | Outdoor coil sensor fault (open or short circuit). | Failed or disconnected outdoor coil thermistor. | Book a service |
| E8 | Outdoor discharge sensor fault (open or short circuit). ESP Digital SRD/SRV. | Failed or disconnected discharge-line thermistor. | Book a service |
| E9 | High or low pressure trip, or phase error (phase error applies to 3-phase models). | High side: dirty/blocked outdoor coil or failed condenser fan. Low side: refrigerant loss or an iced indoor coil from a blocked filter. On 3-phase: a supply phase problem. | Try this first Switch off, clean the return-air filter, and clear debris, plants and stored items from around the outdoor unit. Restart after 5 minutes. If E9 comes back — or if you are on a 3-phase supply — switch off and book a technician. ActronAir notes E9 may not display until it has occurred several times. |
| COOL + LOW flashing 30 s | Anti-freeze protection mode (low capacity mode) — not an E-code. | The indoor coil is running too cold, usually from restricted airflow: dirty return-air filter, too few zones open, or crushed ductwork. | Try this first Clean the return-air filter and open more zones so the system has enough airflow through the indoor coil. |
| HEAT + HIGH flashing 30 s | Overheat safety protection — not an E-code. | Indoor coil overheating in heating mode, usually from restricted airflow (blocked filter, closed zones). | Try this first Clean the return-air filter, open more zones, and check return-air grilles aren't blocked by furniture. |
| HEAT flashing every 8 s | Defrost cycle, or indoor coil pre-heat after defrost — normal operation, not a fault. | Cold, damp weather causing ice on the outdoor coil. Steam or water from the outdoor unit during this is normal. | Try this first No action needed — the indoor fan stays off for a few minutes so cold air isn't blown into rooms. It will resume by itself. |
Wall-hung splits — Aurora (SWB) and Serene (WRC / WRE): codes on the indoor unit display, read via LED flash counts
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| CP | Remote On/Off terminal is open circuit — not a hardware fault. | An external on/off input (BMS, key switch or link) has been removed or opened. | Book a service |
| E0 | Indoor unit EEPROM parameter error. Operation lamp flashes 1×, timer lamp off. | Corrupted memory or a failed indoor control board. | Book a service |
| E1 | Communication error between the indoor and outdoor units. Operation lamp flashes 2×, timer lamp off. | Damaged or loose interconnecting cable, water ingress at the outdoor terminal block, or a failed board. | Try this first Switch the unit off at the wall isolator/breaker for 2 minutes, then restore power and restart. If E1 returns, book a technician. |
| E3 | Indoor fan speed out of control. Operation lamp flashes 4×, timer lamp off. | Blocked filters or air path restricting the fan, or a failing indoor fan motor / control board. | Try this first Turn the unit off, open the front panel, slide out and clean both filters (vacuum or wash and dry fully), refit them, and make sure the indoor air inlet and outlet aren't blocked by curtains or furniture. |
| E4 | Indoor room temperature sensor T1 open or short circuit. Operation lamp flashes 5×, timer lamp off. | Failed room thermistor on the indoor unit. | Book a service |
| E5 | Evaporator coil temperature sensor T2 open or short circuit. Operation lamp flashes 6×, timer lamp off. | Failed indoor coil thermistor or loose plug. | Book a service |
| E7 | Communication error between the display board and the main indoor PCB (Serene WRC/WRE). | Loose ribbon cable behind the indoor display, or a failed display board. | Book a service |
| E8 | Communication error between master and slave indoor units (twin systems). Operation lamp flashes 9×. | Loss of the link between paired indoor units. | Book a service |
| E9 | Another indoor unit malfunction (twin systems). Operation lamp flashes 10×. | The partner indoor unit has faulted — check its own display for the real code. | Book a service |
| EC | Refrigerant leakage detected. Operation lamp flashes 7×, timer lamp off. | The unit has detected a loss of refrigerant charge — a leak in the indoor coil, outdoor coil or pipework. | Switch off & call |
| EE | Water level alarm — condensate not draining (cassette/ducted-type indoor units). | Blocked or kinked condensate drain, a failed condensate pump, or a stuck float switch. | Try this first Turn the unit off and check the outside end of the condensate drain pipe for blockage (leaves, dirt, insects) and that it isn't kinked or lifted. If it's clear, or you can't safely reach it, book a technician — leaving it risks water damage to ceilings. |
| F0 | Overload / over current protection. Operation lamp flashes 1×, timer lamp on. | Excessive current draw at the outdoor unit — compressor or electrical fault. | Switch off & call |
| F1 | Outdoor ambient temperature sensor T4 open or short circuit. Operation lamp flashes 2×, timer lamp on. | Failed outdoor ambient thermistor. | Book a service |
| F2 | Condenser coil temperature sensor T3 open or short circuit. Operation lamp flashes 3×, timer lamp on. | Failed outdoor coil thermistor. | Book a service |
| F3 | Compressor discharge temperature sensor T5 open or short circuit. Operation lamp flashes 4×, timer lamp on. | Failed discharge-line thermistor. | Book a service |
| F4 | Outdoor unit EEPROM parameter error. Operation lamp flashes 5×, timer lamp on. | Corrupted memory or a failed outdoor control board. | Book a service |
| F5 | Outdoor fan speed out of control. Operation lamp flashes 6×, timer lamp on. | Obstruction fouling the outdoor fan, or a failing fan motor / control board. | Try this first Switch off at the isolator and check for leaves, twigs or debris caught in the outdoor fan guard, and that plants aren't touching the unit. Clear it, then restore power. If F5 returns, book a technician. |
| F6 | Indoor coil outlet sensor T2B open or short circuit (free-match indoor units). Operation lamp flashes 7×, timer lamp on. | Failed coil-outlet thermistor, typically located at the outdoor low-pressure valve. | Book a service |
| P0 | IPM (inverter power module) malfunction or IGBT over-current protection. Operation lamp flashes 1×. | Inverter power stage fault or a compressor drawing excessive current. | Switch off & call |
| P1 | Over voltage or under voltage protection. Operation lamp flashes 2×. | Mains supply outside the unit's acceptable range, or a supply cable/connection fault. | Switch off & call |
| P2 | Compressor top high-temperature protection (or IPM module high temperature). Operation lamp flashes 3×. | Compressor overheating — low refrigerant charge, blocked condenser airflow, or a mechanical fault. | Switch off & call |
| P4 | Inverter compressor drive error. Operation lamp flashes 5×. | The drive cannot control the compressor — drive or compressor failure. | Switch off & call |
R-32 wall splits and R-32 Ultra Slim split ducted (URC / CRC / LRC) — alphanumeric EH / EL / EC / PC codes
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| EC0D | Outdoor unit malfunction (general). 14 flashes. | A fault reported by the outdoor unit that isn't broken out into a specific code — check the outdoor board display. | Book a service |
| EC07 | Outdoor fan speed operating outside the normal range. 12 flashes. | Debris fouling the outdoor fan, or a failing fan motor. | Try this first Switch off at the isolator, clear leaves, twigs and plant growth from the outdoor fan guard and around the unit, then restore power. |
| EC51 | Outdoor unit EEPROM parameter error. 5 flashes, timer lamp on. | Corrupted memory or a failed outdoor control board. | Book a service |
| EC52 | Condenser coil temperature sensor T3 open or short circuit. 5 flashes. | Failed outdoor coil thermistor. | Book a service |
| EC53 | Outdoor ambient temperature sensor T4 open or short circuit. 5 flashes. | Failed outdoor ambient thermistor. | Book a service |
| EC54 | Compressor discharge temperature sensor TP open or short circuit. 5 flashes. | Failed discharge-line thermistor. | Book a service |
| EC56 | Evaporator coil outlet sensor T2B open or short circuit (free-match indoor units). 5 flashes. | Failed coil-outlet thermistor. | Book a service |
| EH00 / EH0A | Indoor unit EEPROM parameter error. 1 flash, timer lamp off. | Corrupted memory or a failed indoor control board. | Book a service |
| EH0E | Water-level alarm — condensate not draining. 13 flashes, timer lamp off. | Blocked condensate drain, failed pump, or stuck float switch. | Try this first Turn the unit off and check the outside end of the drain pipe is clear and not kinked. If it's clear or unreachable, book a technician before water damages ceilings. |
| EH0b | Communication error between the two indoor processors. 9 flashes, timer lamp off. | Internal indoor board fault or loose display ribbon. | Book a service |
| EH03 | Indoor fan speed operating outside the normal range. 4 flashes, timer lamp off. | Blocked filters or restricted air path, or a failing indoor fan motor. | Try this first Turn the unit off and clean the indoor filters, and clear anything blocking the air inlet and outlet. Restart after 5 minutes. |
| EH3A | External fan DC bus voltage too low protection. 4 flashes. | Supply or fan-module power fault. | Book a service |
| EH3b | External fan DC bus voltage too high fault. 4 flashes. | Supply over-voltage or a fan-module power fault. | Switch off & call |
| EH60 | Indoor room temperature sensor T1 open or short circuit. 6 flashes, timer lamp off. | Failed indoor room thermistor. | Book a service |
| EH61 | Evaporator coil temperature sensor T2 open or short circuit. 6 flashes, timer lamp off. | Failed indoor coil thermistor or loose plug. | Book a service |
| EHbA | Communication fault between the external fan module and the indoor unit. | Loose or damaged fan module data cable, or a failed module. | Book a service |
| EL0C | Refrigerant leakage detected. 8 flashes, timer lamp off. | Loss of refrigerant charge. R-32 is a mildly flammable (A2L) refrigerant, so a suspected leak needs prompt professional attention. | Switch off & call |
| EL01 | Indoor / outdoor unit communication error. 2 flashes, timer lamp off. | Loose or damaged interconnecting control wiring, or a failed board. Often transient after a power event. | Try this first Switch off at the breaker for 2 minutes, restore power and restart. If EL01 returns, book a technician. |
| PC00 | IPM malfunction or IGBT over-current protection. 7 flashes. | Inverter power module fault or excessive compressor current. | Switch off & call |
| PC01 | Over voltage or under voltage protection. 2 flashes. | Mains supply outside the acceptable range, or a supply cable fault. | Switch off & call |
| PC02 | Compressor top high-temperature protection or IPM module high-temperature protection. 3 flashes. | Compressor or inverter overheating — low charge, blocked condenser airflow, or mechanical fault. | Switch off & call |
| PC03 | High pressure or low pressure protection (some models). 7 flashes. | High side: blocked/dirty outdoor coil or failed fan. Low side: refrigerant loss or iced indoor coil. | Try this first Switch off, clean the indoor filter and clear debris and plants from around the outdoor unit, then restart after 5 minutes. If it returns, book a technician. |
| PC04 | Inverter compressor drive error. 5 flashes. | The drive cannot control the compressor — drive or compressor failure. | Switch off & call |
Cascade and Ultra Slim outdoor units (URC / CRE / LRE / LRC) — codes on the outdoor control board
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| E1 | Indoor / outdoor communication malfunction. | Damaged or loose interconnecting control wiring, or a failed board. | Try this first Power cycle at the breaker for 2 minutes and restart. If it returns, book a technician. |
| F0 | Outdoor over current protection. | Excessive current draw at the outdoor unit — compressor or electrical fault. | Switch off & call |
| F1 | Ambient temperature sensor (T4) malfunction. | Failed outdoor ambient thermistor. | Book a service |
| F2 | Outdoor heat-exchanger (condenser coil) temperature sensor T3 malfunction. | Failed outdoor coil thermistor. | Book a service |
| F3 | Discharge temperature sensor (T5 / TP) malfunction. | Failed compressor discharge thermistor. | Book a service |
| F4 | Outdoor EEPROM malfunction. | Corrupted memory or failed outdoor control board. | Book a service |
| F5 | Outdoor fan speed malfunction. | Debris fouling the outdoor fan, or a failing fan motor. | Try this first Switch off at the isolator, clear debris and plant growth from the fan guard and around the unit, then restore power. |
| J0 | Evaporator (indoor coil) high temperature protection. | Indoor coil overheating in heating mode — usually restricted indoor airflow. | Try this first Clean the return-air filter and clear anything blocking the indoor air inlet and outlet. |
| J1 | Condenser (outdoor coil) high temperature protection. | Dirty or obstructed outdoor coil, failed condenser fan, or recirculating hot air. | Try this first Switch off, clear debris and plants from around the outdoor unit and gently hose loose dirt off the outside of the coil fins. |
| J2 | High discharge temperature protection. | Low refrigerant charge, restriction in the circuit, or blocked condenser airflow. | Switch off & call |
| J3 | PFC (power factor correction) module protection. | Fault in the drive's PFC stage. | Switch off & call |
| J4 | Communication error between the outdoor main board and the compressor drive / IPM board. | Loose internal data cable or a failed board. | Book a service |
| J5 | High pressure protection. | Blocked or filthy outdoor coil, failed condenser fan, or hot air recirculating around the unit. | Try this first Switch off, clear at least 300 mm around the outdoor unit and gently hose the outside of the coil fins, then restart after 5 minutes. |
| J6 | Low pressure protection. | Refrigerant loss, or an iced indoor coil caused by a blocked filter. | Book a service |
| J8 | AC power input voltage protection. | Incoming mains voltage outside the unit's acceptable range. | Switch off & call |
| LP | Low ambient temperature protection. | Outdoor temperature below the operating range — usually self-clearing. | Try this first No action needed in genuinely cold conditions; the unit resumes as ambient rises. |
| P0 | IPM (inverter power module) protection. | Inverter power stage fault or excessive compressor current. | Switch off & call |
| P1 | DC voltage too high / too low protection. | Supply voltage outside range, or a DC bus fault in the drive. | Switch off & call |
| P2 | Compressor top temperature protection. | Compressor overheating — low charge or blocked condenser airflow. | Switch off & call |
| P3 | Ultra-low ambient temperature protection. | Outdoor temperature below the unit's operating range — usually self-clearing as it warms up. | Try this first No action needed if it's a very cold morning — the unit will resume once ambient rises. If it shows on a mild day, book a technician (likely a faulty ambient sensor). |
| P4 | Compressor rotor position protection / inverter compressor drive error. | The drive has lost control of the compressor — stalling or drive failure. | Switch off & call |
| P6 | Compressor voltage protection. | Voltage supplied to the compressor outside safe limits. | Switch off & call |
| P7 | Outdoor IGBT temperature sensor (TH) faulty — open or short circuit. | Failed IGBT temperature sensing circuit on the drive. | Book a service |
WC-02 wired controller (Cascade, Ultra Slim, cassette and ducted indoor units) — note this scheme differs from ducted E-codes
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| E0 | Phase sequence error or phase malfunction. | Incoming supply phases wired in the wrong order or a lost phase — an electrical supply fault. | Switch off & call |
| E1 | Communication malfunction between the indoor and outdoor units. | Loose or damaged control wiring, or a failed board. Often transient after a power event. | Try this first Switch off at the breaker for 2 minutes, restore power and restart. If E1 returns, book a technician. |
| E2 | T1 (room) sensor malfunction. | Failed indoor room thermistor. | Book a service |
| E3 | T2A (indoor coil) sensor malfunction. | Failed indoor coil thermistor or loose plug. | Book a service |
| E4 | T2B (indoor coil outlet) sensor malfunction. | Failed coil-outlet thermistor. | Book a service |
| E5 | T3 or TP (outdoor coil / discharge) sensor malfunction. | Failed outdoor coil or discharge thermistor. | Book a service |
| E6 | Zero-cross check malfunction. | Mains zero-crossing detection failure on the indoor board — supply or board fault. | Book a service |
| E7 | Indoor EEPROM malfunction. | Corrupted memory or failed indoor control board. | Book a service |
| E8 | Fan controller out of control. | Blocked filters restricting the fan, or a failing indoor fan motor / control board. | Try this first Turn the unit off and clean the return-air filter, and clear anything blocking the air inlet and outlet. Restart after 5 minutes. |
| E9 | Communication malfunction between the main PCB and the display board. | Loose ribbon cable behind the display, or a failed display board. (Note: this is NOT the ducted 'low pressure' E9.) | Book a service |
| EA | Compressor overload (has occurred 4 times). | The compressor has repeatedly tripped its overload — mechanical, charge or electrical fault. | Switch off & call |
| EB | IPM (inverter power module) malfunction. | Inverter power stage fault. | Switch off & call |
| EC | Air-clean malfunction. | Fault in the air purification/clean function or its sensing. | Book a service |
| ED | Outdoor malfunction protection. | The outdoor unit has reported a fault — check the outdoor board display for the specific code. | Book a service |
| EE | Full-water malfunction — condensate water level alarm. | Blocked condensate drain, failed pump, or stuck float switch. | Try this first Turn the unit off and check the outside end of the condensate drain pipe is clear and not kinked. If it's clear or you can't reach it safely, book a technician before water damages ceilings. |
| EF | Other fault. | An unclassified fault — the real code will be on the indoor unit's own display. | Book a service |
| F0 | Communication error between the wired controller and the indoor unit. | Loose or damaged controller cable, or a failed controller. | Try this first Power cycle at the breaker for 2 minutes. If the controller stays blank or F0 returns, book a technician. |
| F1 | Elevating fascia panel not closed (auto-lifting panel cassettes). | The motorised panel is obstructed, out of alignment, or its motor has failed. | Try this first Check nothing is obstructing the panel and that it can close freely, then power cycle. If it still won't close, book a technician. |
| P0 | Evaporator temperature protection. | Indoor coil temperature outside safe limits — usually restricted indoor airflow. | Try this first Clean the return-air filter and clear anything blocking the indoor air inlet and outlet. |
| P1 | Anti-cold-air or defrost mode active — normal operation, not a fault. | Cold weather defrost cycle or cold-draught prevention. | Try this first No action needed — normal operation. The fan resumes once the cycle finishes. |
| P2 | Condenser temperature protection. | Outdoor coil too hot — dirty coil, blocked airflow or failed condenser fan. | Try this first Switch off, clear debris and plants from around the outdoor unit and gently hose the outside of the coil fins. |
| P3 | Compressor temperature protection. | Compressor overheating — low refrigerant, blocked condenser airflow, or mechanical fault. | Switch off & call |
| P4 | Discharge pipe temperature protection. | Discharge line too hot — commonly low refrigerant charge or a circuit restriction. | Switch off & call |
| P5 | Discharge high pressure protection. | Blocked/dirty outdoor coil, failed condenser fan, or overcharge. | Try this first Switch off, clear at least 300 mm around the outdoor unit and hose loose dirt off the coil fins, then restart after 5 minutes. |
| P6 | Discharge low pressure protection. | Refrigerant loss, or an iced indoor coil caused by a blocked filter. | Book a service |
| P7 | Over-voltage protection. | Mains supply voltage too high. | Switch off & call |
| P8 | Compressor overload protection. | The compressor has drawn excessive current — mechanical, charge or electrical fault. | Switch off & call |
| PF | Other fault — check the indoor or outdoor unit for the specific code. | An unclassified fault reported to the controller. | Book a service |
Status displays that are NOT faults (outdoor 7-segment display and controllers)
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| boot | Outdoor board booting — shown for 30 seconds at power-up on inverter units. | Normal start-up sequence. On older Classic/ESP Digital boards you instead see the CPU version number, then 8, then the status digit. | Try this first No action needed. Allow 5 minutes before expecting the compressor to start — the system has built-in safety timers. |
| oFF / CooL / HEAt | Unit off / cooling mode / heating mode. Flashing means starting or turning off. | Normal operating status. | Try this first No action needed. |
| dEF, dEF1, dEF2, dEF3 | Defrost active, or 1/2/3 minutes until defrost begins. | Normal cold-weather operation. The indoor fan stops for a few minutes and steam or water from the outdoor unit is normal. | Try this first No action needed — heating resumes automatically within a few minutes. |
| oiLr | Oil return operation. | Normal periodic cycle to return compressor oil. | Try this first No action needed. |
| dr-1 / dr-2 / dr-3 | Demand Response Management active: DRM1 = compressor off, DRM2 = limited to 50% of rated power, DRM3 = limited to 75%. | Your electricity network or retailer has signalled a demand-response event, or a DRM device is wired in. Not a fault. | Try this first No action needed — capacity returns to normal when the event ends. If it's permanently in DRM, ask your installer to check the DRM wiring. |
| ohP / dtP / cPP / hSP | Unit derating: overheat protection / discharge temperature protection / condenser pressure protection / high suction pressure protection. | The unit is deliberately reducing capacity to protect itself, usually because of restricted airflow or extreme ambient conditions. | Try this first Clean the return-air filter, open more zones, and clear debris and plants from around the outdoor unit. If the system keeps derating in mild weather, book a technician. |
| dF / CL (wall splits) | 'dF' = defrosting, 'CL' = Active Clean cycle running on the indoor unit. | Normal operation. During Active Clean the unit runs 20–45 minutes then switches off automatically. | Try this first No action needed — let the cycle finish. |
| fC (wall splits) | Forced cooling mode, entered from the MANUAL CONTROL button on the indoor unit. | The manual control button has been pressed (used when the remote is lost or flat). Cycles forced AUTO (24.0) → forced COOL (fC) → OFF. | Try this first Press the MANUAL CONTROL button again to cycle back to OFF, then use the remote normally once you replace its batteries. |
| C-0 / C-1 / C-2 / C-3 (LR7) | Wall controller address shown for 3 seconds at power-up. C-1 is the master. | Normal power-up display. C-0 means no address assigned yet — if it never changes, the controller isn't talking to the indoor board. | Try this first If the display stays on C-0, power cycle at the breaker. If it still shows C-0, book a technician (likely a wiring or cable fault). |
| PAS / FAL (LR7 self-learn) | Self-Learn commissioning routine passed (PAS) or failed (FAL) on Advance series EVV indoor units. | Shown during installer commissioning of the auto fan mode. FAL usually means duct static is out of range or the filter/grille wasn't fitted. | Book a service |
| FILTER light flashing | Run-hours filter reminder on the wall controller — not a fault. | The microprocessor has counted the preset number of run hours since the last reset. | Try this first Clean the return-air filter (vacuum or wash and dry fully — every 4 weeks is ActronAir's recommendation), refit it, then press ON/OFF to clear the filter light. |
Outdoor unit LED indicators — single-phase soft starter (SS9 / SS1P) and Actron Connect Wi-Fi module
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| SS9 LED — on for 2–3 minutes at power-up | Random power-up delay before a start is allowed. | Normal anti-surge start delay. | Try this first No action needed — wait a few minutes for the compressor to be allowed to start. |
| SS9 LED — on for 2 min 50 s after the compressor stops | Anti-cycle protection delay (a minimum 5 min 50 s start-to-start delay also applies). | Normal compressor protection timer. | Try this first No action needed — this is why a system won't restart immediately after being switched off. |
| SS9 LED — 1 blink (resets after 5 min 50 s) | High running current trip. | Compressor drawing excessive current — mechanical stiffness, high head pressure, or supply problem. | Switch off & call |
| SS9 LED — 2 blinks (resets after 5 min 50 s) | Low running current trip. | Compressor drawing abnormally low current — commonly loss of refrigerant charge or a failed compressor valve. | Book a service |
| SS9 LED — 3 blinks (lock out) | Locked start-capacitor fault. | Failed start capacitor or its wiring. Five lockouts in a row latch the soft starter off until mains is cycled. | Switch off & call |
| SS9 LED — 4 blinks (lock out) | Locked rotor detected. | The compressor is not turning — seized or mechanically jammed compressor, or a failed start component. | Switch off & call |
| SS9 LED — 5 blinks (until voltage is corrected) | Low mains voltage. | Supply voltage below the acceptable range — network issue, undersized cable, or loose connection. | Switch off & call |
| SS9 LED — 6 blinks (lock out) | External run capacitor fault. | Failed run capacitor or its wiring. | Switch off & call |
| Actron Connect ACM-2 — RED LED | Power indicator: on = powered, off = no power. | Off means the module has lost supply — a tripped breaker, unplugged module, or failed power supply. | Try this first Check the system breaker/isolator is on and power cycle for 2 minutes. If the red LED stays off, book a technician. |
| Actron Connect ACM-2 — BLUE LED | Wi-Fi status: solid on = connected; rapid flashing = connecting to network; slow pulse = access point (setup) mode; flashing = no connection. | No connection usually means the router has changed channel/password, the signal is too weak, or the module needs re-pairing. | Try this first Restart your router, then power cycle the air conditioner at the breaker for 2 minutes and re-run the app's Wi-Fi setup. Note this only affects app control — the wall controller still runs the system normally. |
Cascade split system (URC / CRE) — indoor unit display / LED flash counts (extend the existing Cascade group, which currently only covers the outdoor board)
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| F7 | Communication error between the auto-lifting panel and the slim cassette, or auto-lifting panel faulty | Loose/damaged ribbon or plug between the auto-lifting (motorised) front panel and the indoor PCB, or a failed panel motor/limit switch. Applies to slim cassette indoor units fitted with an auto-lifting panel. | Book a service |
| F8 | Auto-lifting panel is not closed | The motorised filter/front panel has not returned to the fully closed position — commonly after cleaning the filters, or something is fouling the panel travel. | Try this first |
| F9 | IPM (inverter power module) malfunction | Inverter power module fault in the outdoor unit — failed IPM/IGBT stage, compressor winding short, low supply voltage or loose DC bus/compressor terminations. Unit will normally lock out and stop. | Switch off & call |
Multi Split system (MRE / BRE indoor heads) — indoor unit display / LED flash counts (MISSING GROUP)
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| CP | Unit switched off by the remote on/off switch (remote on/off terminal open circuit) | External on/off or BMS contact is open, or the link/jumper across the remote on/off terminals has been removed or has come loose. | Try this first |
| E0 | Indoor unit EEPROM parameter error | Corrupt or unreadable configuration memory on the indoor PCB, often after a supply surge or brownout. | Book a service |
| E1 | Communication malfunction between indoor and outdoor units | Interconnect comms wiring open, shorted, reversed, or water-affected; wrong indoor address; failed indoor or outdoor PCB. One of the most common multi-head faults. | Book a service |
| E3 | Indoor fan speed malfunction (fan motor out of control) | Blocked/dirty filter or coil stalling the fan, seized bearings, obstructed fan wheel, faulty DC fan motor or missing RPM feedback to the indoor PCB. | Try this first |
| E4 | Indoor room temperature sensor (T1) malfunction | Open or short-circuit room sensor, or unplugged sensor at the indoor PCB. NOTE: on multi-split this is the ROOM sensor — on Aurora/Serene wall splits E4 is the evaporator coil sensor, so the code must not be shared with the wall-split table. | Book a service |
| E5 | Evaporator coil temperature sensor (T2) malfunction | Open or short-circuit indoor coil sensor, or sensor dislodged from its coil pocket. | Book a service |
| E7 | Communication error between the indoor PCB and the display PCB | Damaged or unseated display ribbon/plug, or a failed display board. | Book a service |
| EE | Water-level alarm malfunction (cassette and ducted indoor types only) | Condensate tray full — blocked or kinked drain, failed condensate pump, faulty float switch, or drain line with insufficient fall. Classic 'unit stops and drips' complaint. | Try this first |
| F1 | Outdoor ambient temperature sensor (T4) malfunction | Open or short-circuit outdoor ambient sensor, or damaged sensor lead at the outdoor PCB. | Book a service |
| F2 | Condenser coil temperature sensor (T3) malfunction | Open or short-circuit outdoor coil sensor, or sensor fallen out of its coil clip (also causes poor defrost). | Book a service |
| F3 | Compressor discharge temperature sensor (T5) malfunction | Open or short-circuit discharge sensor on the compressor discharge line, or unplugged at the outdoor PCB. | Book a service |
| F4 | Outdoor unit EEPROM parameter error | Corrupt configuration memory on the outdoor PCB, typically after a supply disturbance. | Book a service |
| F5 | Outdoor fan speed malfunction | Obstructed or seized outdoor fan, debris in the fan guard, failed DC fan motor or lost RPM feedback. | Book a service |
| F6 | Indoor coil outlet pipe sensor malfunction (sensor located on the outdoor unit low-pressure service valve) | Open or short-circuit T2B pipe sensor at the outdoor manifold, or the sensor is not clamped to the correct branch pipe. | Book a service |
| P0 | Inverter module (IPM) malfunction | Inverter power stage fault — failed IPM/IGBT, compressor winding short to earth, or loose DC bus/compressor terminations. | Switch off & call |
| P1 | Over-voltage or under-voltage protection | Mains supply outside the drive's operating window — brownout, undersized or loose supply conductors, poor neutral, or a site-wide voltage problem. | Switch off & call |
| P4 | Compressor drive malfunction | Inverter cannot start or control the compressor — lost rotor position, compressor mechanically stuck, or failed drive stage. | Book a service |
| P5 | Indoor unit mode conflict | Two or more heads on the same outdoor unit have been set to opposing modes (e.g. one heating, one cooling). A multi-split can only run all heads in the same mode family at once — set all heads to the same mode or turn the conflicting head off. | Try this first |
| P6 | High or low pressure fault — read the MRC outdoor board code to identify which (J5 = high pressure protection, J6 = low pressure protection) | High side: blocked outdoor coil, failed outdoor fan, recirculating hot air. Low side: refrigerant loss, blocked filter/indoor coil, restricted EEV or a closed service valve. | Switch off & call |
Multi Split outdoor unit (MRC) — codes on the outdoor control board (MISSING GROUP)
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| E0 | Outdoor unit EEPROM parameter error | Corrupt or unreadable configuration memory on the outdoor main PCB. | Book a service |
| E2 | Communication malfunction between indoor and outdoor units | Interconnect comms pair open/shorted/reversed, water ingress at a joint, or a failed indoor or outdoor PCB. | Book a service |
| E3 | Communication malfunction between the IPM board and the outdoor main control board | Damaged or unseated internal loom between the inverter (IPM) board and the main outdoor PCB, or a failed IPM board. | Book a service |
| E4 | Outdoor temperature sensor malfunction — coil sensor T3, ambient sensor T4, compressor discharge sensor T5 or indoor coil outlet pipe sensor T2B | Any one of the outdoor thermistors open or short circuit, or unplugged. Each must be ohmed out individually to identify which. | Book a service |
| E5 | Over-voltage or under-voltage protection | Supply voltage outside the permitted range at the outdoor unit — brownout, loose or undersized supply, or poor neutral connection. | Switch off & call |
| E6 | PFC (power factor correction) module protection | PFC stage trip in the inverter — supply distortion/imbalance, choke wiring fault, or a failed PFC/IGBT stage. | Book a service |
| E8 | Outdoor fan speed malfunction | Outdoor fan obstructed or seized, debris in the fan guard, failed DC fan motor or missing speed feedback. | Book a service |
| F1 | Indoor unit A coil outlet temperature sensor malfunction | Open or short-circuit T2B sensor for branch A at the outdoor manifold, or sensor not clamped to the correct branch pipe. | Book a service |
| F2 | Indoor unit B coil outlet temperature sensor malfunction | Open or short-circuit T2B sensor for branch B at the outdoor manifold. | Book a service |
| F3 | Indoor unit C coil outlet temperature sensor malfunction | Open or short-circuit T2B sensor for branch C at the outdoor manifold. | Book a service |
| F4 | Indoor unit D coil outlet temperature sensor malfunction | Open or short-circuit T2B sensor for branch D at the outdoor manifold. | Book a service |
| F5 | Indoor unit E coil outlet temperature sensor malfunction | Open or short-circuit T2B sensor for branch E at the outdoor manifold. | Book a service |
| P1 | High pressure protection (MRC-100AS-4, MRC-110AS-5 and MRC-135AS-5 only) | Blocked or dirty outdoor coil, failed outdoor fan, hot-air recirculation, overcharge, or a restriction on the discharge side. | Switch off & call |
| P2 | Low pressure protection (MRC-100AS-4, MRC-110AS-5 and MRC-135AS-5 only) | Refrigerant loss/leak, closed or partly closed service valve, blocked indoor filter or coil, or a restricted EEV. | Switch off & call |
| P3 | Current overload protection | Compressor drawing excessive current — high head pressure, tight/failing compressor, low supply voltage, or a failing run capacitor/drive stage. | Switch off & call |
| P4 | Compressor discharge temperature protection | Discharge temperature above limit — low refrigerant charge, restricted EEV, non-condensables, or a stuck reversing valve. | Book a service |
| P5 | Condenser high temperature protection | Outdoor coil temperature above limit — dirty coil, obstructed airflow around the unit, failed outdoor fan, or hot-air recirculation in a tight enclosure. | Try this first |
| P6 | Inverter module (IPM) protection | Inverter power stage trip — over-current, failed IPM/IGBT, compressor winding fault, or loose DC bus/compressor terminations. | Switch off & call |
No matching code found.
Meanings vary by series and some codes are model-specific — call 0434 951 341 with the code and your model number and we'll decode it.
Reference compiled from ActronAir service and operation documentation. Codes and meanings are provided as general guidance for the Australian residential range and can differ between model series; no affiliation with ActronAir is implied.
Found your code?
Tell us the code when you book — diagnosis starts before we arrive
Fault finding across Perth from $165 inc GST — all brands, splits and ducted. Quoting the fault code gives us a head start on where to look; we then test and confirm the actual fault on site before any part is ordered, so you never pay for a part you didn't need.
Frequently Asked Questions
Why does the same ActronAir code mean different things?
Because ActronAir has built several generations of controller — LM7/LM24, LR7/NEO, QUE touchscreen, the WC-02 and the wall-split boards — and each has its own code table. E9 is a pressure or phase error on a Classic, a low-pressure trip on an Advance, a comms fault on a WC-02 and a twin-system indoor fault on a Cascade. Always match the table to your equipment before acting.
My QUE screen shows a Failure icon but no code — where's the code?
QUE keeps the E-number in Menu > Technical, which ActronAir reserves for service technicians. The home screen only shows the icon. Menu > Dashboards is safe to browse and shows live component status, which is often enough to describe the problem over the phone.
The FILTER light is flashing — is that a fault?
No. That's a run-hours reminder. Clean the return-air filter, then press ON/OFF to clear it. Similarly, HEAT flashing every 8 seconds is a normal defrost cycle, not a fault.
My system played up but the controller shows nothing — why?
ActronAir's own documentation notes that a fault may not display on the wall controller until it has occurred several times. Intermittent faults can run for weeks before a code appears, which is why a system that misbehaves without a code still deserves a look.
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