What CH21, CH23, CH26, CH29, E9 Means
LG groups these together as indicating a problem with the outdoor unit's compressor or its control circuits, per the same combined troubleshooting article covering the sensor-fault group above. Possible causes LG names: a temporary power issue, a malfunctioning outdoor unit compressor, a compressor drive or protection circuit error, or a faulty electrical component inside the outdoor unit.
Common Causes of CH21, CH23, CH26, CH29, E9
- Temporary power issue
- Malfunctioning outdoor unit compressor
- Compressor drive or protection circuit error
- Faulty electrical component inside the outdoor unit
🔧 One Safe Check You Can Try
Unplug the air conditioner, or turn off its circuit breaker if you can't reach the plug, wait about five minutes, then restore power and check whether the error code has cleared.
⚠ Why You Shouldn't Go Further Than That
- Never disassemble the air conditioner or attempt to replace internal parts yourself - this is compressor and outdoor-unit electrical work, and LG's own warning is explicit that doing so risks fire, electric shock, serious injury, or death.
- If this code reappears after a reset, LG's guidance is to stop using the product and request service rather than repeating the reset, since a compressor-circuit fault can worsen with continued use.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.