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My air conditioner doesn’t cool, why?
Previously we talked about the possible causes for the air conditioning not working or not heating, now we are going to see the possible reasons why the air conditioning does not cool.
Generally when we see that the air conditioner does not cool we tend to think that the problem lies in the lack of gas, we mistakenly think that the gas in an air conditioner has to be changed, replaced or recharged from time to time and this thought is quite incorrect since if the installation of the air conditioner is well done and no pipes have been broken due to friction, vibrations, etc., the gas should not be lost and can remain inside the machine and the installation for years, exhausting the estimated life of a machine (about 15 years) before having to recharge the gas.
Now, let’s look at the possible causes of why air conditioning cools little or not at all.
Possible causes of air conditioning not cooling
Gas leakage
As we said before, possible gas leakage is one of the reasons why window air conditioners do not cool, although it is just as valid for split or duct air conditioners. Gas leakage can be or is found in three parts of our air conditioning: in the refrigeration system (copper pipes and connections/soldering); in the outdoor unit or in the indoor unit, the first being the most common for units that have been installed for a short time and the last two for units that have been installed for longer.
If you think your machine may be missing or leaking gas because the air conditioner is not cooling enough or just ventilating, you may want to read these articles.
Lack of gas, how to detect it?
Dirty filters, one of the big reasons why my air conditioner doesn’t cool
Another problem because the air conditioner does not cool can be due to the fact that we have very dirty filters in the indoor unit. Many people forget that maintaining clean filters is essential not only for the proper functioning of the unit, but also to reduce consumption, not force the operation of the machine and maintain a cleaner environment as these are responsible for filtering the air in our home.
Extremely dirty filters can cause the indoor unit to freeze and in turn you can have problems with dripping into the indoor unit.
You might be interested in: My air conditioner is leaking
Here’s how and why to clean air conditioning filters
Dirty interior fan
We have just talked about the filters and that they have to be kept clean so that our air conditioning works perfectly, this is something that anyone can do without much trouble and it really is one of the few things that we have to do to keep our air conditioning equipment. However, another problem, although much less common, is the accumulation of dirt in the fan (impeller) of the indoor unit. This problem tends to be much more virulent in cool only units and less so in heat pump units, it is also more common in smoking environments, factories or premises where sprays such as lacquers or paints are used as these help to fix the dirt. This cleaning is a very easy way to fix an air conditioner that doesn’t cool if you forgot to do it since it can be your problem if your air is not cool enough.
Dirty inner or outer exchanger
If we have talked about the importance of maintaining clean filters in our air conditioning for its proper functioning, equally or more important is to keep the exchangers clean, as its name indicates where the exchange of cold or heat occurs and is a fundamental part of our air conditioning equipment. All the window air conditioning units, splits or ducts have two exchangers: one in the interior (interior exchanger) and another one in the exterior (exterior exchanger), although in the window air conditioning units it may seem that they are not both together in the same unit.
The heat exchanger of the indoor unit is located just behind the air filters and it is the air filters that prevent it from getting dirty easily. This is one of the most important reasons to keep these filters clean, to prevent that dirt can pass to the exchanger and can dirty or plug it as the cleaning of these components is quite laborious and expensive. Cleaning the filters regularly will greatly help to keep the exchangers in good condition.
A very dirty inner heat exchanger will do the same thing as a very dirty filter: it will lower the gas pressure, lower the electricity consumption and may even freeze the inner unit. This in turn will cause the air conditioner to cool slightly.
On the other hand, the heat exchanger of the outdoor unit will be in charge of “expelling” the heat to the outside and if it is dirty it will prevent this heat discharge. This in turn will cause the unit to rise in pressure, increasing consumption and noise and forcing the operation of the machine, even stopping the unit at high pressure if it is extremely dirty and therefore producing a gradual loss of performance and the air conditioning does not cool or ventilate sufficiently.
To clean these exchangers you can use a soft bristle brush very carefully, avoiding at all times to bend the aluminium sheets that form it, as the air must pass between them. In any case it is recommended to do it with the unit stopped.
Starting capacitors
The starting capacitor is responsible for providing the necessary current to the engines of our air conditioning equipment so that they can start. Generally, these units have three motors: the external fan motor, the internal fan motor and the compressor; and two or three condensers.
Nowadays inverter air conditioners come with the condensers integrated in complex electronic boards, so it is impossible to replace these condensers without having to replace the whole electronic board. But in fixed or non-inverter units this component is usually separate in the outdoor unit but not so much in the indoor unit.
Compressor starting capacitor.
What indications do we have that the capacitor is not working?
We can think that a condenser fails, either the one with the fan or the one with the compressor when everything works except the fan or the compressor and this we can check quite easily. To do this we will turn the unit on cold and at minimum temperature to ensure that the machine will start and we will go to the outdoor unit. Once there it is necessary to wait about three minutes since many machines have a start delay. After that time several things can happen:
- Just starts the fan: we can see this because the fan will turn but we won’t hear the compressor noise, which is usually a deeper, lower noise. In this case the indoor unit will not throw away any cold and therefore our air conditioner does not just cool the air. If we notice this in our air conditioner it is very possible that the condenser will fail. Another option would be for the compressor or the electronic board to fail.
- Starts only the compressor: here it’s easier to see, because we’ll hear a noise and not see anything “move”. If this happens to you, the fault could be the fan capacitor, the fan itself and also the electronic board or some component of it (like a relay). The symptoms in the indoor unit will be that the machine gets to throw some cold but little by little it will stop throwing cold because the outdoor unit will not be able to “take off” the heat.
- Doesn’t start anything: several things can happen here: the condenser may fail and be common to both the compressor and the fan (it is very rare for them to share) or another component that drives both motors may fail. In this case the indoor unit will not cool at all.
Locked external fan
As it happened with the failure in the starting condenser of the external fan, another possibility that exists is that you have the external fan blocked by some object and do not allow that this one rotates avoiding that the machine can be detached of the heat that is generating and therefore it stops for high pressure of gas or for too high temperature of discharge of compressor. Check that the fan rotates correctly and make sure there is nothing interfering with this. There are times when birds will fill a large part of the outdoor unit with sticks, grass and branches to make a nest and this can hinder the fan from rotating.
In this breakdown, if we cannot see the outdoor unit and to know if this is the possible breakdown, if we look, we will see that the air conditioning cools down little and less as the minutes go by, until the time comes when the outdoor unit will stop cooling and just ventilate.
Other possible failures of why my air conditioner doesn’t cool or doesn’t cool enough
As we have seen these are some of the breakdowns or causes why an air conditioner does not cool but not the only ones. With the proliferation of inverter air conditioners many of the failures of the equipment are related to the electronic boards making it quite difficult for someone who does not have the necessary training to determine and repair the failure so it is always advisable to contact the official technical service to find out and solve the problem as the current units in their electronics have become quite complex.
List of official technical services of the best known brands