Quick answer: The LG CH04 error code on a ducted or ceiling unit means condensation isn’t draining from the indoor unit. LG lists a faulty drain pump, a blocked or upward-sloping drain hose, or a dirty filter as causes. If water is leaking, switch it off and book a technician. If not, LG Australia suggests one reset: breaker off for five minutes, then back on. If CH04 returns, leave it off and request service.
Written by Ofek Shamir, owner of The Guys Group · Updated 29 September 2026 · Sources: LG Australia support pages and LG manuals, linked below.
This guide covers LG ducted and ceiling-type systems. Codes can mean different things on LG wall splits and portables, so check your model first.
What does CH04 mean on my LG ducted aircon?
CH04 on an LG ducted or ceiling unit means water is not draining away from the indoor unit. LG Australia says the code “indicates that water (condensate) formed inside the indoor unit is not being drained.” LG’s duct manual lists error 4 as “Malfunction of drain pump”, and LG lists a blocked hose or dirty filter as other causes.
When cooling, condensation collects in a drain pan and a pump lifts it into the drain line. LG USA’s ceiling-unit troubleshooting page lists the causes as “a malfunctioning drain pump, a blocked or upward-sloping drain hose, or a dirty filter.”
Is it safe to keep running my LG aircon with CH04 or water leaking?
No – if CH04 keeps returning or water is leaking from the indoor unit, leave the system off and call for service. LG’s concealed duct owner’s manual lists “Error code is generated by self diagnosis” and “Water leaks from indoor unit” as situations where you should “call the service immediately.”
The same manual says that if anything abnormal happens, such as a burning smell or loud noise, you should stop the unit and turn the breaker off. It also says: “Never try to repair by yourself or restart the system in such cases.”
How do I reset an LG aircon error code?
LG’s first step for most CH codes is a power cycle: turn the air conditioner off at the circuit breaker, wait five minutes, then restore power. A reset can clear a temporary error but does not repair a fault; if the same code comes back, LG Australia says to request service.
- Turn off the air conditioner’s circuit breaker.
- Wait five minutes.
- Turn the breaker back on and check whether the code has cleared.
LG’s instructions use the circuit breaker, not a reset button. Do one reset only. If water is leaking or you notice a burning smell, skip the reset and leave the system off. LG Australia also says that if the breaker won’t switch back on, you should not keep trying it. Request service instead.
Can a dirty filter cause CH04, and what can I check myself?
Yes – LG lists a dirty filter as one cause of CH04, and to help prevent it, LG says to “clean the filter every two weeks and ensure the drainage path is not blocked.” The only part you should check yourself is the return air filter. The drain pump and drain line need a qualified technician.
LG’s duct manual says the air filters “should be checked and cleaned once every 2 weeks or more often if necessary.” You can vacuum a filter or wash it in lukewarm water, but not water of 50°C or more, then dry it in the shade. LG says to disconnect the power supply before cleaning the indoor unit. Don’t open the unit or touch the drain pump yourself. LG warns against repairing the system yourself.
My portable LG shows CH04 or FL – is that the same thing?
No – on an LG portable air conditioner, CH04 (sometimes shown as FL) means the internal water tank or base pan is full. It is not a drain pump fault. LG Australia says this can happen in high humidity, and you fix it by emptying the water through the drain nozzle at the bottom of the unit.
LG says to turn the unit off, unplug it and drain it into a bucket. Ducted systems have no tank to empty, so this advice doesn’t apply to them.
What does CH61 mean on my LG aircon?
CH61 is LG’s overheating protection code. In cooling mode it means the outdoor unit has overheated. In heating mode it means the inside of the indoor unit has got too hot. LG Australia says heating-mode CH61 occurs when the air intake is blocked, “most often due to a clogged filter.”
LG’s duct manual names the code “Outdoor Device Pipe Overheating Error”. LG says the code exists “to prevent fire hazards and product malfunction.” It notes that CH61 “will not automatically clear after inserting clean filters”, so you need a power cycle to clear it.
Why does CH61 keep coming up on hot days?
In cooling mode, CH61 usually means the outdoor unit can’t get rid of its heat. LG Australia points to poor ventilation, objects stacked around the unit, direct sun and dust on the heat exchanger at the back. It says cooling performance may be affected when it is below 18°C or above 48°C outside.
LG’s suggestions:
- Clear objects from all sides of the outdoor unit.
- Consider a sun shade, but fix it securely and never cover the back or sides of the unit.
- If the heat exchanger is full of dust, turn the power off at the breaker first, then wear gloves and brush it from top to bottom with a thick-bristled brush, taking care not to bend the fins.
- In heating mode, clean the indoor unit filter.
Then power cycle the system. LG’s CH61 page says to wait three minutes, and its general guide says five. If CH61 comes back after that, LG says “a professional inspection is necessary.”
What do CH03, CH05, CH07, CH10, CH38 and CH67 mean on an LG ducted system?
These codes point to faults that a cleaning or filter change can’t fix. CH03 and CH05 are communication errors, CH10 and CH67 are fan faults, CH38 means low refrigerant, and CH07 is a mode clash between units. LG’s general first step is one power cycle, then service if the code comes back.
| Code | What LG says it means | What you can do |
|---|---|---|
| CH03 | The indoor unit isn’t receiving a signal from the wired remote controller | Power cycle once, then request service |
| CH05 | Communication error between the indoor and outdoor units | If it appeared after installation or relocation, call the installer. Otherwise power cycle once, then request service |
| CH07 | Units in different rooms set to conflicting modes (for example, one cooling, one heating) | Set all units to cooling or all to heating |
| CH10 | Indoor unit fan fault | LG suggests checking for debris around the fan and removing it. On a ducted system the indoor fan sits inside the ceiling unit, so leave that to a technician and request service |
| CH38 | Low refrigerant (the duct manual calls it “Refrigerant Leakage Error”) | If it appeared after installation, call the installer. Otherwise power cycle once, then contact LG support |
| CH67 | Outdoor unit fan locked | Check that nothing, such as leaves or debris, is blocking the outdoor unit. If it’s clear, request service |
For any code not listed, LG Australia recommends a service technician “as self-resolution may be difficult.” Codes differ between product lines. An LG technician fault-code sheet hosted by ARMA, for example, lists different meanings for CH04 and CH10 on wall-mounted splits. The table above applies to ducted and ceiling-type systems.
For other brands, see Daikin A3 and A5 error codes and Mitsubishi P5, P6 and PA error codes, or our full guide to ducted air conditioner error codes.
Where do I see the error code on my LG ducted system?
On an LG ducted system the error normally shows on the wired wall controller as “CH” followed by a number, such as CH04 or CH61. If your system is connected to the LG ThinQ app, the app’s Smart Diagnosis feature can show errors that don’t clear after a restart, along with troubleshooting guidance.
Ceiling cassettes may show the code as flashing LEDs instead; LG suggests filming them with your phone to count the blinks.
How often should I clean the filter, and how do I clear the filter light?
LG says to clean the air filter every two weeks, or more often if needed. Its wired controllers show a filter cleaning indicator when cleaning is due. LG’s PREMTB001 controller manual has a “Filter Sign Clear” setting for switching the indicator off after you’ve cleaned the filter.
LG explains why it matters: “Dust in the filter may reduce cooling/heating efficiency and cause high electricity bill. Therefore, be sure to clean the filter whenever cleaning time is expired.” The indicator also cancels itself after a set period, so no light doesn’t mean a clean filter.
Technician or cleaner: who should I call?
Error codes like CH04, CH05 or CH38 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 LG.
Sources
- [LG Air Conditioner] Guide to Error Codes, LG Australia
- [LG Air Conditioner] How to Resolve Error Code CH 61, LG Australia
- [LG Air Conditioner] How to read error codes, LG Australia
- (Mobile/Portable) Inspection code CH04, LG Australia
- LG Concealed Duct Air Conditioner owner’s manual, LG Australia
- Ceiling Cassette, Ceiling Concealed Duct owner’s manual (MFL67870342), LG
- How to troubleshoot error codes CH03 and CH04 on your LG ceiling-mounted air conditioner, LG USA
- PREMTB001 wired remote controller owner’s manual, LG
- LG air conditioning fault codes (technician sheet, hosted by ARMA)
