Gas leak

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What is a gas leak in an air conditioner?

A gas leak is a loss of refrigerant in the refrigerating circuit of an air conditioning unit. It can be caused by a failure in the installation, a defect in the manufacturing of the indoor or outdoor unit, a failure in the manufacturing of the materials used for the installation or by a wear of the materials used in both, machine or installation.

Given this problem, the first thing we need to be clear about is exactly that, that the failure of our air conditioning is actually caused by a lack of gas and therefore we have had a leak of refrigerant, so first of all we advise you to check the symptoms that usually give an air conditioning with a lack of gas.

Air conditioning symptoms with lack of gas

Knowing that our air conditioner is running low on gas, now is the time to see why it is leaking and to locate the gas leak.

Although it was mentioned in another article I would like to emphasize that no air conditioner consumes gas, nor wastes it, nor loses it unless there is actually a gas leak, I have heard many times from customers who tell me things like:

“the gas has probably been used up“

“Don’t these devices need to be recharged every few years?“

Well, actually no, air conditioning units of any model should never be recharged with gas unless a gas leak is lost, this leak may be due to poor installation, some fault in the machine or by some wear and tear of both, if any ‘technician’ or who calls technical tells you that, is lying or cheating.

Another point that we must take into account is that if there is a lack of gas, the solution is not only to refuel, the solution is to locate the gas leak, solve it and once we are clear that everything is correct to perform the gas refueling, since refueling and forgetting without having located and solved the problem only postpones that problem because yes or yes the gas will be lost again sooner or later.

 How to make a gas charge properly

Possible causes of a gas leak

As we have discussed, there are three major causes for gas leaks, installation, manufacturing and wear and tear, within these three possibilities we will investigate each of them and their most common possibilities.

Gas leaks produced by the installation

As human beings that we are, even the best air conditioning installer can have a bad day and that this will affect us in a gas leak, this type of leak if we detect it in time -installation guarantee- should be completely in charge of the installer himself, since it is his responsibility to do the work correctly, however sometimes a bad installation and its consequent leak is not seen until years after it was installed and there we will hardly be able to claim.

That is why it is important to know even before our air conditioner is installed what points of it we should check to make sure everything is correct and we will not have problems in the future.

These are the most critical points to check and where the vast majority of gas leaks per installation occur

Nuts and bolts: Generally in domestic equipment both the indoor and outdoor unit come with nuts where the copper pipes of the installation are connected, these pipes have to be passed from the indoor unit to the outdoor unit and then connected to both machines, The most common way to make these connections is to use the nuts that come prepared on the machines and are made with a ‘belling machine’ to give a conical finish to the pipe and to join it perfectly with each of the machines. This operation is done twice – small pipe and large pipe – in each of the units -inside and outside- and it is quite common that this belling is not done correctly, the nut is over-tightened when joining it or even the opposite, it is not tightened enough.

All three possibilities are prone to gas leakage, some immediately and some after a while.

Welding: Another way to carry out the installation is to weld the pipes – especially in the indoor unit -, this work is quite simple but many times there are also mistakes and refrigerant leaks. Locating a weld is more complicated because unlike the nuts, these do not have to be in a fixed location, in many occasions the installation or pre-installation has been short and it is necessary to add pipe and the correct way to do it is to weld one more piece of pipe, so there can be welds in several points of the installation and in very varied locations, if we find it we have to proceed in the same way as with the nuts: water, soap and patience.

How to detect it?

The way to detect these two types of leaks if you are still leaking gas is very simple and easy, we only need water, soap and a brush.

To do this, we will make a soapy mixture with a soap that produces as many bubbles as possible -dishwasher, for example- and we will wet the brush and then ‘paint’ the connections or welds in both machines with that soapy mixture. We must carefully observe if bubbles are formed due to the effect of the gas coming out if there is a gas leak. If we don’t see how the bubbles multiply it means that there is no leak or it is very small – this operation has to be done with the unit stopped and with the gas open, if we are in the middle of the installation and the gas has not been opened yet it is obvious that we will not have pressure in the pipe and it will be impossible for it to make bubbles.

If the machine is out of gas it will not make any bubbles, but we can check the connections, welds and nuts because when gas is lost some oil is usually lost which is mixed with the gas, so any trace of oil usually indicates a gas leak or an old gas leak repaired if it was not cleaned up when repaired.

However, even if some oil appears, it would be necessary to verify that this is where the leak is by calling the technical service and making a leakage test with nitrogen. A leakage test should never be made with oxygen or with the cooling gas itself, since oxygen could make the external machine explode and by using cooling gas we are intentionally throwing that gas into the atmosphere, something that is punishable by law.

How to perform a leak test correctly

Leaks caused by a poorly executed drainage: Drainage? Are you crazy? What does drainage have to do with gas? This type of leak is the one that surprises both installers who have never seen anything like it and customers who do not understand how the drain can affect a copper pipe, but they are much more common than anyone can imagine, but why does it happen?

The leaks through a drain are produced by the lack of a siphon or that it is too small, this siphon as in any drain of our house prevents the gases, odors and vapors from the general drainage go up it and produce bad odor in our home, but not only prevent the bad smell, also prevent gases such as methane that accumulates in these drains end up in our homes. This combination of gases degrade the copper that air conditioning units are made of to such an extent that they completely destroy the copper pipe, producing leaks that are also irreparable, since not only is the point where the leak is in bad condition, but all the copper is weak and there is no way to weld it.

How to detect it?

To detect this leak due to drainage gases we will have to tune our nose well, since the first symptom that something is not working well will be indicated by the bad smell that the machine produces when it is turned on, another very easy way is visually, since this problem blackens the copper pipe and this is something that should not happen.

You may be interested in knowing other possible causes of air conditioning smells, you can see it in this link:

Causes of a bad-smelling air conditioner

Gas leakage due to manufacturing failure

This point can be subdivided into two possibilities, failure in the manufacture of machine/s or failure in the manufacture of the material used for the installation -generally copper tube-.

Manufacturing leaks in air conditioning machines

Manufacturing leaks in machines are not very common but they do exist, in general the renowned brands of air conditioning usually have a very high quality control and all units are tested in the factory both electrically and refrigeration, however the failures exist and these are the most common:

• Leakage in internal exchanger.
• Leakage in the external exchanger.
• Leakage in copper piping from outdoor unit.
• Other leaks.

How should we act?

This type of leak is more complex than the one produced in the installation, not because it is more difficult to repair, but because it is more difficult to locate since you already have to open the machine or machines completely to check their internal parts. If any type of leak of this type appears, it is advisable to call the official technical service of the brand and have them check it.

Leakage due to manufacture in material used in the installation

Here we already spoke of the gas leaks more complicated to locate, but fortunately for all, also they are of long the most difficult ones that take place, in this case the problem usually comes by the copper pipe, these although they are made with the maximum technology can in very strange cases have small pores although the tube is completely new, locating the leak in a defective copper pipe does not bring any major problem, the problem lies in locating the exact point of that leak to be able to solve it, in these cases the solution is to forget about that installation and make a new installation, since it will be faster, easier and cheaper than looking for the exact point and repair it.

Wear and tear gas leaks

We enter the last point, gas leaks produced by wear or deterioration of materials.

In these cases there is one that is usually the most common and is produced by the shock or friction of two copper pipes, this process is long in time and occur only in the outdoor unit, because this is where more copper pipes are and also where most of the vibrations.

In order to detect it in time we will have to listen to the outdoor unit, as a rule in these situations we usually hear abnormal metallic noises inside the outdoor unit, which are usually produced by the collision of two pipes with each other or of a copper pipe on some metal sheet of the unit, we can detect it even better if we open this unit and check the pipes to see if there are two pipes glued together, if this is the case we would have to separate them with our hands enough so that this collision does not happen again or place some kind of rubber block between them to avoid possible leaks.

You can review the other possible causes of air conditioning noise at this link:

Possible causes for a noisy air conditioner

There are also other extremely rare possibilities such as leaks in the compressor, 4-way valve, liquid accumulator, etc., but these are very rare cases.