LG HVAC Error Code 10

Error code 10 on LG HVAC systems signals one of two faults depending on the model. On LS902HPV, LS122HPV, LA09xHV, and LA12xHV inverter units, the outdoor PCB has detected an open or shorted discharge pipe thermistor. On all other inverter and PTAC models, it means the outdoor fan motor is not rotating or not confirming rotation to the board. On 10/13 SEER units, it indicates an indoor fan failure.

No. Error code 10 indicates either a missing temperature sensor input or a fan motor that is not operating. Running the system without a functioning discharge thermistor removes compressor overheat protection, and operating without proper fan airflow can cause refrigerant pressures to reach unsafe levels. The unit should remain off until the fault is diagnosed and repaired.

A power reset may temporarily clear the error code, but it will return as soon as the system attempts to run and detects the same fault condition. If the thermistor is out of spec, the fan motor is not rotating, or the PCB is not supplying proper voltage, the underlying problem must be repaired for the code to stay clear. Repeated resets without repair can lead to additional component damage.

Some basic checks, such as inspecting wiring connectors for corrosion or physical damage, can be done by a knowledgeable homeowner. However, diagnosing this fault properly requires measuring DC bus voltage (up to 310V DC) at motor leads and testing thermistor resistance with a multimeter, which involves live high-voltage circuits. These steps should be performed by a qualified HVAC technician.

Repair costs vary depending on the failed component. A replacement discharge pipe thermistor typically costs in the range of $20 to $80 for the part, while an outdoor fan motor can range from $80 to $250 or more depending on the model. Control PCB replacement is generally the most expensive repair, often falling between $150 and $500 for parts alone. Labor costs will add to these figures.