# Mini split not cooling or blinking: what to do

Updated: 2026-10-24 · https://pros411.com/en/guides/hvac/mini-split-not-cooling

## Short answer

Count the blinks and write the pattern down: it is an error code. Set the remote to "Cool" (the snowflake) a few degrees lower and check its batteries. Turn the power off, lift the front panel, rinse the mesh filters and let them dry. Then reset it: breaker off for about 5 minutes, then back on. If it still blinks or blows warm, call a technician with the code.

> Safety first: Turn the unit off at the breaker or the outdoor disconnect before you lift the panel or touch the filters. Use a sturdy step ladder, since the indoor unit is mounted high. Never spray water into the unit or open the outdoor unit.

## How to check a mini split that is not cooling

![Cartoon ductless mini split scared and blinking its light while it blows warm air into a hot room](https://pros411.com/img/guias/mini-split-not-cooling.webp)

1. **Warm air and a blinking light.** Count the blinks and the pause, or read the code on the display. Write it down before you reset anything.
2. **Remote on Cool, a few degrees lower.** Look for the snowflake, not the sun, the drop or the fan. Set it a few degrees below the room. Weak remote? Replace the batteries.
3. **Power off and rinse the filters.** Turn it off at the breaker. Lift the front panel, slide out the mesh filters, rinse them with lukewarm water and let them dry.
4. **Filters back, wait 5 minutes, power on.** Put the dry filters back. Leave the breaker off about 5 minutes, then turn it back on and start the unit from the remote.
5. **Cold air and a steady light.** Give it 15 minutes. If the light blinks again or the air stays warm, call a technician and tell them the code.

## What the blinking means

Most mini splits flash a light or show a short code when a sensor, the outdoor unit or the connection between them has a problem. Some also blink to remind you to clean the filters. Codes differ by brand, so look yours up in the manual. A reset clears a passing glitch; a code that comes back needs a technician.

## Also check outside

- Clear leaves, grass and plants around the outdoor unit, with the power off.
- Look for ice on the outdoor unit or the copper lines while it is cooling.
- Make sure the outdoor fan spins when the unit is cooling.

## What not to do

- Do not spray water or cleaners into the unit or onto the fan.
- Do not reset it over and over. If the code comes back, call.
- Do not run it without the filters.
- Do not add refrigerant yourself. It requires certification, and low refrigerant means a leak.

## When to call an HVAC technician

- The light blinks again after a reset.
- It blows warm air with clean filters and the right mode.
- Water drips from the indoor unit.
- There is ice on the outdoor unit or the copper lines in cooling mode.
- The outdoor unit does not start or makes a loud noise.

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## Frequently asked questions

### Why is my mini split blinking?

A blinking light is usually an error code or a filter reminder. Count the blinks or read the code, look it up in the manual and try a reset. If it comes back, call a technician.

### How do I reset my mini split?

Turn it off at the breaker or the outdoor disconnect for about 5 minutes, then turn it back on and start it from the remote. Many units also have a small manual button under the front panel.

### Why is my mini split running but not cooling?

Often the wrong mode on the remote, dirty filters or a blocked outdoor unit. Low refrigerant, a bad sensor or a failed part need a technician.

### How often should I clean mini split filters?

About every 2 to 4 weeks while you use it, more often with pets or dust. Rinse them with lukewarm water and let them dry before you put them back.

### What does the snowflake mean on my mini split remote?

It is cooling mode. The sun is heat, the drop is dry mode, which cools only a little, and the fan icon only moves air.

### Can I clean the inside of a mini split myself?

Only the filters. The coil and the blower wheel need a deep cleaning by a technician, usually once a year, especially if it smells musty.