Summer has come and we seek relief at home. We turn on the air conditioner, ready to enjoy the coolness, but it does not work as it should: a discomfort similar to a broken boiler in winter. What are the reasons causing this annoying situation? Let's find out together.

Why is the AC running but not cooling?

It's one of those unexpected occurrences that may happen when you turn on the air conditioner for the first time after a long period. It no longer produces cold air or does not work properly. The much-desired comfort while temperatures rise rapidly seems to turn into an unachievable dream.

There are several reasons why the air conditioner no longer blows cold air. 

• The lack of refrigerant gas is one of the main causes. The air conditioner is turned on, but the cooling does not start. Gas level is probably below the limit required by the air conditioner model.
• The external unit could be another factor affecting the poor performance. It may be clogged with dust and dirt that has accumulated over time. The external unit dissipates heat from the indoor environment. If this action is hindered by debris buildup, the result is minimal or there is no cooling at all.
• Similarly, the problem could be related to the internal unit and its reduced ventilation. Unclean filters, especially due to dust, produce feeble cold air. Regularly cleaning is necessary to avoid such situations.
• Apart from the filters, the fan can also get clogged, reducing the airflow of the internal unit or causing a malfunction.
• Finally, a possible reason may be right in front of us: incorrect settings on the remote control. In winter, the air conditioner might have been used for heating and the settings could have remained the same in the meantime. Check what the device’s display indicates.

Like a boiler or any other heat generator, the air conditioner requires proper attention and supervision from a specialised technician.

It's essential to rely on the expertise of a qualified professional, especially for refrigerant gas recharge. The technician must have a proper certification, which attests the skills to handle fluorinated gases: they are the artificial chemical substances that impact the environment and contribute to the greenhouse effect.

How to check AC gas level

As mentioned earlier, the low level of refrigerant gas is among the main reasons for the lack of cold air. The gas is odourless and colourless, leaving no clear trace to indicate whether the air conditioner lacks gas and to assess its level at first glance.

One more reason to request the intervention of a specialised technician.

On the other hand, a clue for the user to understand if there are any hitches with gas’ level, is the presence of ice on the pipes near the outdoor unit, caused by the low temperature of the refrigerant. The system is, therefore, unable to cool the rooms because the refrigerant is not circulating in the right way.

Before proceeding with a recharge, a comprehensive check by a professional technician is essential. The low level may also result from:

• faults in the pipes;
• problems with the heat exchanger, which cools liquids and gases with minimal energy consumption;
• wear and tear or cracks that compromise the air conditioner's functionality.

Performing a recharge would be futile if the loss is likely to continue.

Why is my air conditioner blowing hot air?

The lack of gas generates the emission of warm or hot air from the air conditioner.

Therefore, if the gas level is too low because it is running out or due to leaks in the system, the pleasant sensation of coolness is only an unfulfilled wish.

It is essential to remember that the refrigerant gas has a medium to long lifespan, exceeding ten years.

In the absence of leaks, it is necessary to further analyse the causes and check that the fan is not malfunctioning. If it emits less cool air, it means that the air conditioner is struggling to cool the indoor environment, and the unit starts blowing warm air.

It should be considered that external elements, located in the outdoor unit, can weigh on its poor functioning: not only the dust accumulated over time but also some debris that may have entered the structure.

Cleaning and inspection should always be carried out by qualified technicians because their intervention helps understand the real reason for the malfunction and identifies any damages.

Air conditioner blockage

The air conditioner may also be affected by a lockout. In this case, a warning light appears on the generator’s display. 

The causes include:

• an electrical overload that damages the internal circuit board;
• dirty filters in the indoor unit.

In the latter case, after turning off the air conditioner, the filters should be removed from the indoor unit and cleaned. After eliminating residues and dust, they should be carefully rinsed and left to dry in the open air before remounting them.

The electrical overload can result from incorrect electrical connections or interruptions in the household power supply. It cannot be fixed by the user: it is necessary to contact a specialised technician.