LG · Ductless air conditioner
CH66
Power reset onlyerror code
LG CH66 indicates a communication-line or piping-connection issue between indoor and outdoor units.
Market, product family, and model applicability
US · en-US · LG inverter air conditioners covered by the cited US guide
product family applicable: The official source applies at the product-family level. Exact controls can still vary by model.
Check the official model/manual lookup (opens in a new tab)What you can do now
Contact the installer for an installation-related display; otherwise use the documented reset.
- During normal use, disconnect power for five minutes and restore it.
Stop and get service when
Installation-related CH66 belongs with the installer; persistent CH66 requires service.
- Contact the installation technician if CH66 appeared after installation or relocation.
- Request LG service if CH66 persists.
Do not do
Do not inspect wiring, alter piping, or handle refrigerant.
Communication wiring and piping are professional-only.
If the message returns
Contact the installer or LG service according to when CH66 appeared.
Source and scope
Official manufacturer source- Market and locale
- US · en-US
- Product family
- inverter split-system air conditioners
- Official source last checked
- July 26, 2026
- Review status
- Automated evidence review completed · Owner-delegated approval
LG
[LG Air Conditioner] Guide to Error Codes · Official error-code index
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