What to Check First
- Preheating operation: When starting the heating mode, this function raises the temperature of the indoor unit piping in advance to prevent cold air from blowing directly on you.
- Defrost operation: This function melts frost (ice) that forms on the cold surface of the outdoor unit during heating, preventing a drop in heating performance.
- 1. Check the target temperature: The air conditioner stops blowing air when the indoor temperature reaches or approaches the target temperature. If you want warmer air, use the remote control to set the target temperature higher than the current temperature.
- 2. Wait during preheating operation (initial heating): When you first turn on the heating, the blower fan will not run until the piping temperature rises above 22℃. Wait a moment, and warm air will gradually blow out once preheating is complete.
- 3. Wait during defrost operation (during heating): If frost forms on the outdoor unit during heating, the air conditioner temporarily stops heating and starts the defrost operation to melt it. At this time, the indoor unit louver angle is minimized to block cold air. Once the frost is completely melted, heating will automatically resume.
- In cold weather when the temperature around the outdoor unit drops significantly below minus 15 degrees Celsius, preheating and defrosting may take longer than usual.
- During the initial heating stage, even after the piping is preheated and air begins to blow, it may temporarily feel lukewarm because it is similar to body temperature.
- Display: 'Defrost/Preheating' text or 'Water Drop' LED lights up.
- Indoor unit fan: Stopped (OFF).
- Indoor unit louver: Floor-standing models maintain their set position; wall-mounted models close.
Why This Can Happen
Symptoms can have more than one cause, and the correct steps depend on the exact model, installation and operating conditions. Use the checks above to narrow the issue before service.
Safety and Model-Specific Guidance
Frequently Asked Questions
What should I check first for [LG Air Conditioner] Heating stops and defrost/preheating icon appears?
Preheating operation: When starting the heating mode, this function raises the temperature of the indoor unit piping in advance to prevent cold air from blowing directly on you.
When should I stop troubleshooting and contact LG?
Stop if the product shows signs of electrical damage, burning, leaking near electrical components, or if the recommended checks do not resolve the issue. Use LG USA support for model-specific service guidance.
Does this guidance apply to every LG model?
Not always. Controls, error codes and service steps can differ by model. Confirm the exact model number and follow the linked LG USA article for model-specific instructions.
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