Not Cooling
LG Air Conditioner
Severity:What Does This Error Mean?
An LG AC that runs but does not cool is most commonly caused by a dirty filter, the remote set to Fan mode, or a blocked outdoor unit. Clean the indoor filter, select Cool mode, and check that the outdoor unit fan is spinning.
Affected Models
- LG Artcool Series
- LG Dualcool Series
- LG Standard Plus Series
- LG DUALCOOL Premium
Common Causes
- Indoor air filter blocked — most common cause
- Remote or controller set to Fan or Dry mode instead of Cool
- Outdoor unit coil dirty or fan obstructed
- Refrigerant low — leak in the system
- Outdoor unit in heat mode (reverse-cycle confusion)
How to Fix It
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Select Cool mode on the remote.
Press the Mode button on the LG remote until the snowflake (Cool) icon appears. Also confirm the set temperature is at least 2 degrees below the current room temperature. The AC will not cool if it thinks the room is already at the target temperature.
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Clean the indoor air filters.
Open the front panel of the indoor unit and slide out the mesh filters. Wash under running water and allow to dry fully before reinserting. LG recommends cleaning filters every 2 weeks — a heavily blocked filter dramatically reduces cooling output.
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Check outdoor unit airflow.
The outdoor unit must expel hot air freely to cool effectively. Ensure there is at least 30 cm of clearance around all sides. Remove any leaves, debris, or garden furniture blocking the airflow.
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Run LG Smart Diagnosis.
LG ThinQ-compatible units support Smart Diagnosis via the LG ThinQ app. Open the app, select the AC, and run a diagnostic scan to identify any fault codes the system has logged.
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Check for ice or frost on indoor unit.
If ice is forming on the indoor unit coils or refrigerant pipes, the system is either severely under-cooled (very dirty filter) or low on refrigerant. Switch to Fan Only mode for 30 minutes to defrost, then assess.
When to Call a Professional
If the outdoor unit is frosted or refrigerant lines are icing up, the system has a refrigerant leak. Only a licensed technician can diagnose and recharge the system.