Daikin Air Conditioner Not Cooling — Fix Guide

What Does This Error Mean?

A Daikin AC that runs but does not cool is most often caused by a dirty air filter, the unit running in Fan Only mode, or low refrigerant. Clean the filter first, confirm the remote is set to Cool mode, and check the outdoor unit for ice build-up.

Affected Models

Daikin Cora Series
Daikin Alira X
Daikin US7
Daikin FTXM Series
Daikin Zena

Common Causes

Air filter blocked — restricts airflow and reduces cooling capacity
AC set to Fan mode instead of Cool mode
Outdoor unit coil dirty — heat cannot be expelled
Refrigerant low due to a leak
Outdoor unit fan not spinning

How to Fix It

Confirm the AC is in Cool mode.

Press the Mode button on the remote until the snowflake (Cool) icon is displayed. If the unit is in Fan mode, it will blow air but produce no cooling at all. Also check the set temperature is below the room temperature.
Clean the indoor air filters.

Open the indoor unit cover and remove the mesh filters. Wash them under running water, allow to dry fully, and reinstall. A heavily blocked filter reduces airflow to the point where the unit appears to not cool at all. Daikin recommends cleaning filters every 2 weeks.
Check the outdoor unit.

Inspect the outdoor unit — the fan should be spinning and hot air should be exhausting from the top when in cooling mode. If the outdoor unit is iced over or the fan is not spinning, the unit has a fault requiring a technician.
Check for ice on the indoor unit.

Turn the unit off and switch to Fan Only mode for 30 minutes. If ice melts from the indoor unit's evaporator coils, the filter was severely blocked or refrigerant is low. After defrosting, run on Cool again and monitor.
Check that vents are not blocked.

Ensure furniture or curtains are not blocking either the indoor unit's air intake (top or front) or its outlet (bottom). Blocked airflow reduces cooling output significantly.

When to Call a Professional

If cleaning the filter and outdoor coil does not restore cooling, and ice is forming on the indoor unit or refrigerant lines, the system has a refrigerant leak. Only a licensed refrigeration technician can recharge refrigerant.