Lack of gas

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How to detect a gas shortage

Previous clarifications

First of all I would like to clarify, for those who still have doubts about gas refills in air conditioning equipment, that these should not be periodically refilled as some people think and others make us believe. If an air conditioning unit is in perfect condition when installed and this installation was done correctly, we should not charge gas unless a leak occurs, either in some part of the machine or in the installation.

This is because the refrigerant circuit consisting of indoor unit + outdoor unit + installation must or should be completely watertight and therefore not allow any gas to escape. It should also be clarified that gas does not ‘wear out’ and can do its job perfectly throughout the life of our air conditioning, so any ‘technician’ who tries to sell us that we need to recharge gas because gas wears out, is not a technician, is cheating us or both.

Once this clarification is made, let’s see how we can detect whether or not a leak actually exists.

How to tell if our air conditioner is out of gas

To detect a lack of refrigerant associated with a gas leak we have two ways to do it, with pressure gauges and without them, as generally a person who is not a frigorist and is not dedicated to repairing air conditioners does not usually have a pressure gauge to measure the pressure in his storage room, let’s start by trying to detect it if we have a lack of gas without this tool.

Symptoms

The easiest and also quite reliable option in this case is to look at the symptoms we have in our air conditioning, the symptoms most associated with a leak and lack of gas are:

Symptoms while running in cold mode

• My air conditioner doesn’t cool or doesn’t cool very much: If your machine has been working well in the previous days but you have noticed that it is ‘harder’ to cool or the air doesn’t seem so cold, this could be a symptom of lack of gas. Check that on the outdoor unit both the fan and the compressor start.
• The copper pipe in the outdoor unit freezes: A freeze in the outdoor unit piping is a clear symptom of refrigerant shortage, but can also be associated with other problems. However, this freezing will not occur in our machine if the refrigerating circuit has been completely emptied, it will only happen if even having a leak, this has not produced a total loss of gas and we still have something inside the refrigerating circuit. -generally it is when it has little gas left-.

 

• Indoor unit freezes:Just as the piping – connections – of the outdoor unit can freeze, a partial lack of gas can cause the heat exchanger of the indoor unit to freeze or frost

• Indoor unit drips: Sometimes a drip from the indoor unit can indicate a lack of gas, this occurs because as we mentioned in the previous point sometimes the indoor unit freezes and freezes a lot, even creating a block of ice in the indoor unit that once we stop it begins to thaw producing an overflow of the tray that collects the condensate and producing this drip, at other times the ice is released and may appear droplets by the interior fan.

These are some of the easiest symptoms to detect a lack of gas and therefore a gas leak associated with that loss if no measuring tool is available. However, although any of these symptoms alone may indicate that there is a lack of gas, they can also be produced for other reasons. Here is a link where you can review the most common reasons why your air conditioner is not cooling.

Most common reasons for not cooling an air conditioner

Symptoms running in heat pump

• My heat pump doesn’t heat up or heats up little: Just as a lack of gas can stop a machine from pulling cold or cool it less, when this machine is running on a heat pump the symptoms of a lack of refrigerant are the same: it pulls little heat or no heat at all. As we said, this is a symptom of a possible lack of gas but in heat pump mode another symptom can also appear in the indoor unit: the indoor fan does not turn on. This happens because air conditioning units in heat pump mode ‘wait’ for enough heat in the indoor unit to start pulling air so that it is not cold and annoying. Some units after a while, even though it is not hot enough, it ends up pulling air, but in others it doesn’t even start and it stops completely.
• The heat exchanger of the outdoor unit is frozen: As it happened in cold mode, when there is a lack of refrigerant as we are now running our air conditioning in heat mode or heat pump, the indoor unit and outdoor unit change their functions and it is therefore the outdoor unit that receives the cold and the indoor unit that receives the heat, so this time there is this lack of gas will be the outdoor unit that can get frozen.

As in cold mode, these symptoms can indicate that there is a lack of gas and therefore a leak, but these symptoms do not always tell us 100% that this is the reason. There are other possibilities that can cause these symptoms to occur and make our machine not heat, you can see the most common causes of why a heat pump does not heat in the following link:

Common causes of why air conditioning doesn’t heat up

How to tell if you are running low on gas with gauges

The best way to detect a possible lack of gas and therefore a leak of refrigerant is by using pressure gauges. Pressure gauges are an essential tool for any refrigeration technician and indicate the pressure in the refrigeration circuit of an air conditioning unit, a cold room or any appliance that has fluorinated gas or refrigerant inside.

Generally two pressure gauges are used – high and low pressure – since any air conditioning unit when in function has in its refrigerating circuit two parts so to speak, one part of high pressure and another of low pressure.

Having looked over this, let’s see how to check an air conditioning unit with pressure gauges for that lack of refrigerant.

Checks

The first thing we will do is connect the low pressure gauge to the low pressure port of the machine and the high pressure port to the high pressure port. Many machines do not have two outlets and we have to make do with a single outlet that is located on one of the two keys on the outside unit: the 3-way key or the low pressure pipe key -large tube-. Once this has been done, we will check the pressure and when the unit is stopped we should have a pressure of approximately 8 to 15 kg depending on the type of refrigerant gas in the unit and the ambient temperature.

• R-22 and R-407 should have a pressure between 8 and 11 kg.
• R-410 a pressure of approx. 13-15 kg.

If once the pressure gauges are placed we see that the pressure is much lower than indicated or is at 0 kg we must be clear that our machine lacks gas and therefore a major gas leak, since to reach this end must lose all or almost all the gas.

If, on the other hand, the pressure is similar to the one indicated above, we will proceed to put the machine into operation and let the unit work for about 15 minutes so that the pressure is sufficiently balanced. After these minutes we will check the working pressure and it should be similar to this:

• R-22 and R-407 should have a low pressure of about 4 kg and a high pressure of about 20 kg.
• R-410 the pressure should be approximately 8 kg in low and 30 kg in high.

*If there is only one pressure connection on the unit, it is normal that when the unit is cold this connection is low pressure and when it is hot it is high pressure.

If these pressures are correct and we have both the internal and external unit working, we will have to think that our machine is neither lacking nor leaking gas. If, on the contrary, the pressures are lower than they should be – both high and low – it is very likely that we will have a lack of gas.

In the case that a pressure is lower than normal and another higher than normal we should think that the problem comes from another reason, valves, obstruction, etc.

If, on the contrary, you have detected that your machine may have a lack of gas and therefore a gas leak, surely this article will help you, where we explain the most common places where these leaks usually occur and how to locate them.

Gas leak, where and how to locate it