LG S18ET NSJ Dualcool Smart: CH05 and CH06 Error Diagnosis

⚠️ SAFETY WARNING / SERIOUS RISK. This appliance operates with critically dangerous components (High Voltage or Gas). DIY repair of critical devices can be fatal and is prohibited by law. Physical intervention legally requires qualified specialized technicians to issue compliant safety certificates. ReeFix provides this diagnosis EXCLUSIVELY for educational and informational purposes.

Diagnosis LG S18ET NSJ Dualcool Smart: CH05 Errors and CH06

CH05 (communication error between indoor and outdoor units) and CH06 (NTC heat exchanger sensor anomaly of the indoor unit) errors on LG Dualcool Smart (S18ET NSJ) are closely related. The most probable cause (55-60%) for both is a fault or thermal drift of an NTC sensor for the indoor unit heat exchanger of an LG Dualcool Smart (S18ET NSJ)&mkcid=1&mkrid=711-53200-19255-0&siteid=0&campid=5339148621&toolid=10001&mkevt=1). A blockage due to the CH06 code can indeed interrupt correct serial communication, generating the CH05 code in cascade.

When the CH06 error occurs, the LG air conditioner suddenly stops and often shows six consecutive flashes on the split's LED. This behavior indicates that the sensor no longer correctly detects the evaporator temperature, preventing the air conditioning cycle from starting for safety.

Less probable is a problem with the interconnection wiring between the two units (25-30%) or a fault in the external electronic board for LG Dualcool Smart (S18ET NSJ)&mkcid=1&mkrid=711-53200-19255-0&siteid=0&campid=5339148621&toolid=10001&mkevt=1) (10-15%). Prolonged exposure to humidity and temperature fluctuations often deteriorates sensors or oxidizes wiring contacts. A professional Fluke digital multimeter is essential for measuring sensor resistance and verifying communication voltage on the serial line.

Operational decision: For your safety and the complexity of the intervention, which involves mains voltages and refrigerant gases, always contact a qualified technician. DIY is discouraged and potentially dangerous. Replacing the entire air conditioner is rarely necessary for these codes, as repair by replacing the sensor or restoring the wiring is highly cost-effective and efficient.