LG Air Conditioner Error Code CH04
The unit has detected that condensate water is not draining away and has stopped to prevent a leak. A blocked or kinked drain hose is the most common cause; on indoor units with a built-in pump, the pump or its float switch may have failed.
Also shown as: 04, 4
Applies to: Indoor units with a drain pump or float switch (ceiling and ducted types; optional on wall units)
Common causes
- Drain hose kinked, crushed or blocked
- Algae or sludge built up in the drain pan
- Drain pump failed
- Float switch stuck or failed
What to check, in order
- Turn the unit off and check the condensate drain hose where it leaves the building: straighten kinks and clear any blockage at the outlet.
- If water is dripping from the indoor unit, keep it switched off until the drain runs freely, so the pan cannot overflow.
- Turn the unit off with the remote, then switch off its circuit breaker (or unplug it) and wait at least five minutes before switching back on.
- If the code returns with the drain running freely, the pump or float switch needs a technician.
Clear the code and test
- Fix what the checks above found first — a filter cleaned, an obstruction removed, the breaker restored. Clearing the code without fixing the cause only brings it back.
- Restore power at the breaker and switch the unit on with the remote.
- Run the unit in cooling or heating for ten to fifteen minutes and watch whether the code returns; some codes only appear after the compressor has run for a while.
- If the unit runs with no code, the fault is cleared. If the code returns, write down the code and whether the indoor or outdoor unit shows it before calling a technician — it speeds up the diagnosis.
When to call a professional
Most cases are solved by the checks above. Book a technician if any of these apply:
- The code comes back after you have run the checks and a test cycle.
- You smell burning, see sparks or scorch marks, or the breaker trips.
- Water is leaking and you cannot stop it.
- The fix needs panels opened beyond what your manual describes, or a part tested with a meter, and you are not set up for that.
When you call, give the brand, the code CH04, your model number (on a label on the side of the indoor unit) and the checks you already ran. It shortens the visit.
Parts that may be involved
Drain pumpFloat switch
Parts are model-specific. Find your model number first — usually on a label on the side of the indoor unit — and match the part to that number before ordering.
Questions people ask about CH04
What does CH04 mean on a LG air conditioner?
CH04 means: Drain pump / float switch error: condensate level too high. The unit has detected that condensate water is not draining away and has stopped to prevent a leak. A blocked or kinked drain hose is the most common cause; on indoor units with a built-in pump, the pump or its float switch may have failed.
Can I fix LG CH04 myself?
Start yourself: the checks on this page cover the causes you can reach without opening the machine up. If they point to a faulty part, testing or replacing it is usually a technician job.
How do I clear LG CH04?
Fix what the checks above found first — a filter cleaned, an obstruction removed, the breaker restored. Clearing the code without fixing the cause only brings it back. Restore power at the breaker and switch the unit on with the remote. Run the unit in cooling or heating for ten to fifteen minutes and watch whether the code returns; some codes only appear after the compressor has run for a while.
Sources checked
The meaning and checks for this code were checked against the sources above in November 2026. Codes vary by model and region; if your manual lists a different meaning for your exact model, follow the manual.