LG HVAC Error Code 27

Error code 27 means the inverter compressor experienced an amperage spike exceeding 100 amps, even if only for a fraction of a second. The system shuts down automatically to protect the compressor and inverter components from damage. This code points to issues with the power supply, compressor condition, airflow restriction, or the reactor component in the drive circuit. A full electrical and mechanical inspection is required before restarting the unit.

No. The system shuts itself down specifically to prevent further damage when this error occurs, and attempting to force it to run would risk destroying the compressor, the inverter board, or both. The root cause of the 100A spike must be identified and corrected before the unit is returned to service. Operating with this fault unresolved could also create a fire or electrical hazard.

Repair costs vary widely depending on the root cause. If the fix is simply cleaning the outdoor coil or tightening reactor connections, labor costs alone may be in the range of $100 to $300. A reactor replacement typically adds $50 to $200 in parts. Compressor replacement is the most expensive outcome and can range from $1,000 to $3,000 or more depending on the system size and installation complexity. An inverter board replacement generally falls somewhere between those two extremes.

Some causes, like clearing debris from around the outdoor unit to restore proper airflow, can be handled without specialized tools. However, checking compressor winding resistance, measuring supply voltage under load, and testing reactor resistance all require a multimeter and knowledge of inverter-driven systems. Compressor replacement and inverter board diagnosis should be handled by a certified HVAC technician due to the high voltages and refrigerant handling involved.

A reset may temporarily clear the error and allow the unit to restart, but if the underlying cause is still present the code will return, often immediately. In cases of a compressor winding failure or a serious power supply problem, repeated restarts can cause additional damage. The error should be diagnosed and resolved before relying on a reset as a solution.