[LG Air Conditioner - Heating] Airflow Stops and a Defrost, Preheat, or Water Droplet Indicator Appears

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1. 1. Preheating raises the indoor unit's pipe temperature when heating first starts to prevent cold air from blowing out.
2. 2. Defrosting melts any frost that forms on the outdoor unit while the heater is running.

※ Note: Both preheating and defrosting are normal operations designed to ensure efficient heating. Rest assured, your unit is working properly.

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When the target temperature and the indoor temperature are the same or similar, the airflow will stop.

➔ If the target temperature is set too low, try raising it.

When Defrost or Preheat appears on the display, airflow may temporarily pause.

When using the unit in heating mode in cold weather, the Defrost or Preheat indicator may light up on the display, and airflow may pause for a few minutes.
This is a normal preheating step to make sure warm air comes out. Please wait a moment, and warm air will gradually start coming out.

※ Note: When heating first starts, if the unit’s piping temperature has not yet warmed up to 22℃ (72℉), the louvers will open but the fan will temporarily stay off.
Even after the unit warms up and heating begins, the initial airflow may feel lukewarm or slightly cool because the air is still cooler than your body temperature.

During preheating or defrosting, the Preheat, Defrost, or water droplet indicator will light up on the display.

When defrost mode starts, the air conditioner briefly runs in cooling mode to warm up the outdoor unit and melt the frost.
During this time, the indoor unit temporarily pauses and the louvers adjust to prevent cold drafts.

[How to check]

※ Note: The indicator for preheating or defrosting may vary by model.

What is preheating and defrosting?

1. 1. Preheating raises the indoor unit's pipe temperature when heating first starts to prevent cold air from blowing out.
2. 2. Defrosting melts any frost that forms on the outdoor unit while the heater is running.

※ Note: Both preheating and defrosting are normal operations designed to ensure efficient heating. Rest assured, your unit is working properly.

[When heating first starts] Preheating (Water droplet indicator)

1. Step 1. Preheating to warm up the indoor unit

   When heating starts, warm refrigerant circulates to heat the indoor unit, so warm air does not come out immediately.
   If the temperature around the outdoor unit drops below -15°C (5°F), preheating may take longer than usual, or lukewarm air may blow for an extended period.

2. Step 2. Preheating indicator turns on when the target temperature is reached

   When the room temperature exceeds the target temperature, the fan stops and the unit enters standby mode with the Preheating indicator on.

[During heating] Defrosting (Water droplet indicator)

1. Step 1. Defrosting to melt ice on the outdoor unit heat exchanger

   During heating, the indoor unit blows warm air while the outdoor unit blows cool air.
   Moisture in the air can freeze on the surface of the outdoor unit's heat exchanger.
   Because ice buildup on the heat exchanger reduces heating performance, the system automatically starts a defrost cycle to melt the ice.

2. Step 2. Defrosting to prevent internal ice on the outdoor unit heat exchanger

   The defrost cycle may also run automatically based on internal piping temperature or ice buildup that isn’t visible.

[Frost buildup on the outdoor unit]

[During defrosting]

[Defrosting completed]

[Air conditioner operating status during defrosting]

Air conditioner operating status during defrosting list

During Defrosting/Preheating	Floor-standing air conditioner	Wall-mounted air conditioner
Display	Defrost/Preheat indicator	Defrost/Preheat/Water droplet LED turns on
Indoor fan	OFF	OFF
Indoor unit louvers	Current setting	Closed
Outdoor fan	OFF	OFF
Outdoor unit compressor	ON	ON

Move left or right to check the contents.

If the issue persists after following these steps, contact LG Customer Support for assistance.

This guide was created for all models, so the images or content may be different from your product.