ErrorCodeDoctor
LG · Air Conditioner
LG Air Conditioner CH66 error code
Difficulty: Hard
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Cost: $0–$200
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Duration: 5m
The CH66 error appears on LG inverter air conditioners and indicates a problem with how the indoor and outdoor units are connected — either the communication wiring or the refrigerant piping. If the error appeared right after installation or relocation it is very likely a connection issue that the installation technician needs to fix. If it appeared during normal use it may be a temporary fault caused by an unstable power supply and a power cycle may clear it. A persistent CH66 after resetting always requires a professional inspection.
Common causes
- Communication wiring between indoor and outdoor units was not connected correctly during installation
- Refrigerant piping connection is loose or incorrectly fitted
- Unstable power supply causing a temporary communication fault
- Wiring between units was damaged during relocation
How to fix it
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1
If the error appeared right after installation or relocation contact the installation technician immediately
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2
Ask them to inspect the communication line and piping connections between the indoor and outdoor units
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3
If the error appeared during normal use unplug the power cord or turn off the circuit breaker and wait 5 minutes
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4
Restore power and check if the error has cleared
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5
If CH66 keeps returning after a power cycle the unit needs inspection by a service technician