Air conditioner not cooling: the most common causes and what to do

If an air conditioner is not cooling, first check the settings, filters and outdoor unit – you can solve these causes yourself. If that does not help or an error code appears on the display, it is probably a fault that a technician needs to assess.

Check it yourself

1. Mode and temperature – is cooling mode set (not fan or dehumidification) and is the temperature lower than in the room?
2. Remote control batteries – does the unit respond to commands?
3. Filters – clogged filters significantly reduce output.
4. Outdoor unit – is it covered, clogged with leaves or in direct sunlight with no airflow?
5. Windows and doors – with the windows open, the air conditioner cannot keep up.
6. Circuit breaker – has the outdoor unit’s breaker tripped?

When it is a fault

• an error code appears on the display or remote control,
• the outdoor unit does not start or switches off repeatedly,
• ice forms on the pipes or indoor unit,
• water drips from the indoor unit (Air conditioner condensate: why it forms and why an air conditioner drips),
• the unit makes unusual noises,
• output is falling gradually – there may be a refrigerant leak (Topping up air conditioner refrigerant: when it is needed).

What to do if there is a fault

1. Switch off the air conditioner if ice is forming or water is dripping.
2. Note down the error code and the approximate age and type of the unit.
3. Do not interfere with the refrigerant circuit – it may only be opened by authorised technicians.
4. Book a service.

Prevention

Most summer faults can be prevented by spring preparation and regular servicing – How to prepare your air conditioner for the summer season.

Air conditioner service in Bratislava

We diagnose and repair Daikin air conditioners in Bratislava and the Bratislava Region. Write to us and mention the error code – it helps with diagnosis. Read more on the Air conditioner service page.