Quick answer: Ducted air conditioner error codes mean your system has stopped or limited itself to protect a part. Write down the code and your model, switch the system off and check the return air filter. The manufacturers say most codes need a qualified technician, not a DIY repair. A few can point to a clogged filter or drain.
Written by Ofek Shamir, owner of The Guys Group · Updated 29 September 2026 · Sources: manufacturer manuals and support pages, linked below.
What does the error code on my ducted air con mean?
An error code means your ducted air conditioner’s self-diagnosis has found a problem and a protection has operated, so the unit has stopped or limited itself to avoid damage. The code tells you which protection tripped, not which part failed. The same code can also mean different things on different models, so a technician still has to find the cause.
Mitsubishi Electric says that when a code appears, “The protection devices have operated to protect the air conditioner.” Fujitsu General warns that “the same LED count or code can represent a different fault on another model”.
Where do I find the error code?
On most ducted systems the error code shows on the wall controller, usually as a letter followed by one or two digits. On some systems the indoor unit’s lamps blink in a pattern instead. If your home has a separate zone controller or touchscreen, that screen can show codes too. Note which screen the code is on before you look it up.
- Daikin: a two-digit code on the controller. Some controllers show “Error: Push Menu button”.
- Mitsubishi Electric: the remote controller display, or a flashing operation lamp on the indoor unit with a wireless remote.
- Fujitsu: the green power indicator blinks and an “Error” screen shows the code.
- ActronAir: “E” followed by digits on the wall controller.
Find your brand: which guide covers my code?
Ducted air conditioner error codes differ by brand, so start with yours. Codes and meanings can also vary by model, so confirm against your manual.
| Brand | Where the code shows | Codes explained |
|---|---|---|
| Daikin | Controller screen; some show “Error: Push Menu button” | Daikin guide: A3, A5, A6, C4, E3, U0, U4 |
| Mitsubishi Electric | Remote controller display, or a flashing lamp on the indoor unit | Mitsubishi guide: P5, P6, PA, P1, P2, P4, P8, P9, E4, E6, E7, EE, Fb, PL |
| LG | “CH” and a number on the wired controller | LG guide: CH04, CH61, CH03, CH05, CH07, CH10, CH38, CH67 |
| ActronAir | “E” and digits on the wall controller | ActronAir codes below: E3, E5, E6, E9, E10 |
| Fujitsu | Blinking green power light and an “Error” screen | Fujitsu General error codes |
For Samsung, Panasonic, Mitsubishi Heavy Industries and other brands, check your owner’s manual for the code list.
What do ActronAir E3, E5, E6, E9 and E10 codes mean?
ActronAir wall controllers show faults as “E” followed by digits. Its LM7 manual says: “When EXX is displayed on the wall controller, take note of the digits after E and contact your installer.” ActronAir’s own error FAQ pages describe the common codes like this. Meanings depend on your controller (LM7, NEO, QUE and others), so check the page for yours.
- E3: “typically is associated with sensors” (NEO controller)
- E5: “typically is associated with loss of communication” (LM7 controller)
- E6: “typically is associated with the discharge temperature” (NEO controller)
- E9: “typically is associated with low pressure” (NEO controller)
- E10: “typically is associated with high pressure” (NEO controller)
All five point to parts a technician has to test. ActronAir’s FAQ pages include a short video for each code on each controller.
Is the code from my air con or my zone controller?
An error code on a ducted system can come from the air conditioner itself or from a separate zone controller, such as MyAir, iZone or AirTouch. Zone controllers can show their own codes about zoning, sensors or wiring, and those are not air conditioner faults. Some can also pass on the air conditioner’s own codes, so check which one you are looking at.
Fujitsu General says MyAir codes “are not Fujitsu indoor or outdoor unit fault codes.” AirTouch says its controller “can display its own specific error codes” as well as the air conditioner manufacturer’s codes.
Is it serious? Can I keep using it?
Treat any ducted error code as a reason to stop the system rather than keep running it. Daikin, Mitsubishi Electric, Fujitsu and ActronAir all tell owners to note the code, stop the system and contact their dealer, installer or authorised service personnel. The code alone does not tell you how serious the problem is. A technician’s diagnosis does.
Daikin’s ducted manual says: “Write down the fault code and then stop the operation.” Mitsubishi Electric’s says: “Do not attempt to repair this equipment by yourself.” Switch off straight away if you smell burning, water leaks from anywhere other than the drain pipe, or a breaker keeps tripping.
Things that look like faults but usually aren’t
Without an error code, the manuals call these normal:
- No restart straight after stopping. Mitsubishi Electric says to wait about three minutes. ActronAir mentions built-in 5-minute safety timers.
- A delay after the power comes on. Daikin says to wait one minute. Mitsubishi Electric units can show “PLEASE WAIT” for about 3 minutes.
- Heating pauses in cold weather. The outdoor unit is defrosting. Mitsubishi Electric says this takes about 10 minutes, and Fujitsu says up to 15 minutes.
- Water or steam from the outdoor unit while heating. ActronAir, Mitsubishi Electric and Fujitsu all describe this as normal.
Can I reset the error code myself?
Once at most, and only the way your manufacturer allows. Daikin’s and Mitsubishi Electric’s ducted manuals don’t give owners a reset for fault codes; they say to stop the system and call. LG Australia’s first step for most of its codes is one power cycle: circuit breaker off, wait five minutes, then power back on. If you try a power cycle, do it once. If the code comes back, leave the system off and book a technician.
Repeated resets won’t fix a real fault. Fujitsu General’s procedure for MyAir zone-controller codes is to turn the system off “at the mains for 15 minutes” and retest. Don’t leave the power off for long periods either: Daikin’s ducted manual says that after a long time off, the main power should be turned on “6 hours before restarting operation”.
When do I need a technician?
Call a qualified air conditioning technician whenever an error code comes back or won’t clear. Do the same if water is leaking, you smell burning, the breaker keeps tripping or the system won’t run at all. The manuals tell owners not to repair the unit themselves, and Daikin states there are “NO USER SERVICEABLE PARTS” inside a ducted air conditioner.
For a burning smell, Fujitsu says to “immediately stop operation, turn off the electrical breaker and consult authorized service personnel.”
My ducted aircon stopped after a storm or power cut. What should I do?
First check that the power is back and that the air conditioner’s circuit breaker hasn’t tripped. Many ducted systems restart on their own: Daikin says the system “may automatically restart immediately after the power supply recovers”, and ActronAir controllers can restart in the same mode if that option is set. If a fuse has blown or the breaker has tripped, Daikin’s manual says: “Please contact and notify qualified technicians to check.”
LG Australia says that if the breaker won’t switch back on, “do not attempt to reset it repeatedly”. Communication codes can follow power problems: Daikin lists “Outdoor unit power supply is OFF” as a cause of U4, and LG says CH05 may be caused by an unstable power supply. If the code doesn’t clear, call a technician. If the power was off for a long time, Daikin says to turn the main power on “6 hours before restarting operation”.
My controller screen is blank and shows no code. What now?
A blank controller usually means the system has no power, so there is no code to read. Daikin’s manual says that if the system does not operate at all, check for a power failure and wait until power is restored, then check whether the fuse has blown or the circuit breaker has tripped, and if so contact qualified technicians. With a wireless remote, Mitsubishi Electric says a blank or faint display means the batteries are low: “Replace the batteries and press the Reset button.”
If your home has a zone controller or touchscreen as well as the wall controller, check whether both are blank. If the power is on and the controller stays blank, call a technician.
Could my ducted air con just need cleaning?
Sometimes, but usually not when an error code is showing. Most ducted codes are electrical, sensor, communication or refrigerant faults with nothing to do with dirt. A few codes list a clogged filter, a blocked drain or a dirty coil among their possible causes. Weak cooling or heating without a code is often linked to a dirty return air filter.
These fault codes list dirt or blockage among their causes:
- Daikin: A3 (drain), A5 (clogged air filter) and E3 (dirty outdoor heat exchanger). See Daikin A3 and A5 error codes.
- Mitsubishi Electric: P5 and PA (drain) and P6 (clogged filter). See Mitsubishi P5, P6 and PA error codes.
- Fujitsu: E:53, a drain pump error that lists “Hose clogging” as a cause.
- LG: CH04 (drainage) and CH61 (overheating). See LG CH04 and CH61 error codes.
Even then, dirt is a common cause, not the only one. A failed pump, float switch or sensor can trigger the same code.
What does the filter light mean, and how do I turn it off?
The filter light, or a “time to clean filter” message, is a maintenance reminder, not a fault code. On most ducted systems it comes on after a set number of running hours, not because it has measured a dirty filter. Clean the return air filter as your manual describes, then clear the reminder on the controller. If yours never comes on, check the filter anyway.
ActronAir says its controller “monitors the accumulated run time”. On its LM7 and LM24 you clear it with the ON/OFF button. Fujitsu says: “Clean the filter. Afterwards, turn the FILTER indicator off.” The reminder can also be switched off. Fujitsu has a setting that hides it, and on Mitsubishi Electric’s PEAD ducted units it can be set to “No filter sign indicator”. Daikin says to clean filters at the start of summer and winter; ActronAir says every 4 weeks.
Why is water leaking from my ducted air con or ceiling?
Water coming through the ceiling usually means condensate from the indoor unit isn’t draining away, often because the drain line is blocked or the drain pump or float switch has failed. Stop the system and have a technician check it. Several drain error codes exist for this, and the manufacturers direct owners to their installer or dealer, not a DIY fix.
Daikin’s manual says: “If you think the drain is blocked stop the air conditioner and contact your installer.” Related codes include Daikin A3, Mitsubishi Electric P5 and PA, Fujitsu E:53 and LG CH04. Samsung says drain pan and drain pipe cleaning “must always be performed by qualified personnel.”
Why is my ducted air con on but not cooling?
If your ducted system runs but doesn’t cool properly, the manuals suggest checking the simple things first. Is the return air filter clogged, the outdoor unit blocked, a door or window open, or the set temperature wrong? If those are fine, or an error code is showing, a technician needs to find the cause.
Two codes can point to a dusty outdoor unit: Daikin E3 and LG CH61 in cooling mode. Daikin only tells owners to clear obstacles around the outdoor unit. LG suggests switching off at the breaker and gently brushing dust off the outdoor coil. Anything more is technician work.
Does an error code mean I need a new air conditioner?
Not on its own. An error code tells you which protection tripped, not how big the repair is. The manufacturers’ cause lists for common ducted codes are mostly single parts, such as a sensor, drain pump, float switch, fan motor or circuit board, and LG says some errors are temporary ones “caused by power instability or other electrical factors” that a reset can clear. Whether to repair or replace is a call for a qualified technician once they have diagnosed the fault.
What should I write down before I call?
Before you call, write down the exact error code and where it showed: the wall controller, a zone controller or the indoor unit’s lamps. Also note your model and serial number, and what the system was doing when it stopped. ActronAir asks owners to have the “Model No. and Serial No.” ready, and Mitsubishi Electric asks for the model name and what appeared on the display.
Who should I call: a technician or a cleaner?
Most error codes need a qualified air conditioning technician. If your filter reminder is on, the return air filter is caked with dust or the system just hasn’t been cleaned in a while, The AC Cleaning Guys can help. Our ducted system clean is $349 + GST and includes a new filter, cleaning of the aluminium duct foils from the filter through to the return duct, a professional sanitise, and an airflow check and test run, with no mess left behind. If you prefer to keep your current filter, our Deep Scrub & Sanitise option is $229 + GST: the duct foils deep-scrubbed through to the return duct, a professional sanitise, and an airflow check and test run. See our ducted aircon cleaning service or call 1300 380 090.
The AC Cleaning Guys is an independent cleaning company, not affiliated with or authorised by any air conditioner or zone-controller brand named on this page.
Sources
- FDYAN / FDYUAN ducted operation manual, Daikin Australia
- Understanding symbols on Daikin controllers, Daikin Australia
- Simple self-diagnosis by malfunction code, Daikin
- PEAD-M ducted operation manual, Mitsubishi Electric Australia
- PEAD-M ducted installation manual, Mitsubishi Electric Australia
- PEAD-M service manual, Mitsubishi Electric
- ARTG30–54 ducted operating manual, Fujitsu General Australia
- Error codes, Fujitsu General Australia support
- MyAir error codes, Fujitsu General Australia support
- ARTH ducted service manual, Fujitsu General Australia
- LM7 / LM24 wall controller operation manual, ActronAir
- Error FAQs, ActronAir (code pages: E3, E5, E6, E9, E10)
- [LG Air Conditioner] Guide to Error Codes, LG Australia
- Troubleshooting error codes CH03 and CH04, LG
- Error code CH61, LG Australia
- Duct type air conditioner user manual, Samsung
- Solving error codes, AirTouch
