Any, even the most high-quality and reliable air conditioner, has a moment in operation when its power starts to fall. This becomes noticeable by the fact that the microclimate in the room begins to change over a longer period of time than before.
With regular preventive cleaning of the climatic equipment, the loss of the refrigeration process occurs for only one reason - the leak of freon. There is a general misconception that gas injection is a rather labor-intensive process that cannot be done independently and, especially, at home. However, it is not. you can independently charge the air conditioner at home, which will save a decent financial amount, which is necessary to pay for the work of service specialists.
Air conditioning power loss occurs for several reasons:
- The evaporator and other internal parts become dirty. indoor unit in a split system.
- More often this happens due to a decrease in the amount of freon that flows through the connecting fittings, resulting in a decrease in cooling capacity.
Description of malfunctions of the air conditioner that can lead to power loss.
What is preferable - to refuel or refuel the air conditioner?
Most often, a household split-system does not require a full refueling, but a partial refueling is enough. There are several reasons for this. For instance,
The air conditioner was being repaired. After that, it must be refilled.
On the split system, the air temperature is set to 19 degrees, and it heats the air to 21 degrees. This means that the air conditioner needs refueling.
For any climatic equipment, about 8% of the refrigerant is lost per year, which makes it necessary to refuel any split system once every couple of years.
Before refueling, it is necessary to clarify the amount of freon in the system in order to refuel as much as needed, since if the amount of freon is not enough, the desired result will not be obtained, and if the amount is excessive, the compressor may fail.
The following options for refueling HVAC equipment:
By pressure. To determine the right amount of refrigerant, it is enough to carefully read the documents that came with the equipment. When connected to a collector air conditioner, the freon pressure in the system is displayed. Having learned the value of pressure necessary for the normal operation of the air conditioner, it is easy to calculate the amount of freon that is necessary for refueling.
By weight. Using this option is advisable in order to completely fill the device, since before using it all the freon is pumped out of the air conditioner, and then the volume of the system is again filled with freon. For this purpose, special scales are used. Having learned the amount of gas in the tank, fill the required amount.
There is another way to fill the climate equipment with freon, only it is used most often after repairing equipment, or in cases of air entering the system. This is a refill on a measured glass. Having noticed air bubbles in the inspection window of the Freon block, the system is filled with freon before the bubbles are squeezed out of the pipeline. After that, the gas is vented to the norm of filling the equipment when the required pressure in the system appears.
Preparing the air conditioner for refueling or refueling
You need to know that independent preparation and refueling of climate equipment is carried out by specialized tools, and freon is also required. So think about where you will take all this.
Care must be taken to ensure that the vacuum pump has a pressure gauge and a check valve to prevent oil from entering the freon system.
In large cities, it is possible to rent these tools. The rental fee will be less expensive than paying for the services of a professional from a service center.
- The preparation for refueling the air conditioner is considered to be the study of evaporative and condenser tubes, and the integrity of the freon line.
- After conducting an external inspection, pump nitrogen into the system, which is in a gaseous state, through a gearbox equipped with a pressure gauge. After reaching the filling volume of the split system of a particular model, nitrogen automatically ceases to flow into the system. You will need to monitor the pressure gauge to see if the pressure in the system drops. If there is no drop in pressure, then the system is tight, and the leak of freon occurred for a reason that is not associated with damage to the circuit.
- After checking the system (as professionals say - the system is pressed), they perform its evacuation, for which they use specialized devices: a collector and a vacuum pump.
- Then, the vacuum pump is connected to the device, for which a collector is used. Then open the gas valve of the manifold and turn on the vacuum pump.
- When the gauge needle reaches the minimum value, turn off the pump and close the manifold gas valve.
This is the last stage of preparation for refueling HVAC equipment.
After crimping and evacuating the system, do not try to disconnect the collector from the air conditioner!
Detailed instructions for refueling the air conditioner
To make independent refueling of climatic equipment, the use of some devices is necessary:
- Digital weights;
- Digital thermometer;
- Gauge manifold;
- A set of hex keys.
The use of a two- or four-position collector is allowed. The on-off collector is used for evacuation and refueling of HVAC equipment, however, at the same time, the hose of additional equipment is reconnected, resulting in airlockwhich must be released by opening the fluid valve located on the manifold.
When using a four-position collector, these steps will not have to be performed. This device has a completely sealed system in which there is no contact with air.
- Before starting work, it is necessary to open the locks, which are located in the service connections of the air conditioner - this will allow to release the remaining freon from the device.
- When the gas is completely out of the equipment, locks are shut off.
Now you are offered information on how to refuel HVAC equipment using freon using the overheat rate method. Overheating is an indicator of the difference in the temperature of superheated steam and the boiling temperature of freon. The temperature indicator of superheated steam is taken by an electronic thermometer (while the device must be turned on). The boiling point of the gas shows a low pressure gauge located on the manifold.
How to refuel an air conditioner or split system?
The normal indicator of the difference in these temperatures should be between 5 and 8 ° C. If the difference exceeds 8 ° C, it is necessary to fill the split system with freon, the amount of which is insufficient.
- To fill the system, a cylinder filled with freon is installed on the scales.
- Then the scales are set to “zero”, after which they open the valve on the cylinder, and, at the same time, just for one second, open the liquid valve on the manifold, releasing excess air that is in the hoses.
- Then the gas valve located on the manifold opens. During the period when refueling is carried out, there is an increase in pressure in the system and a drop in temperature on the thermometer.
- These actions are performed until the difference between the pressure gauge and the thermometer, which are located on the gas pipe of the split system, reaches 5 - 8 ° C.
- The final step is to shut off the gas valve on the manifold, and then the valve on the cylinder with freon is closed. Looking at the scales, you will find out how much gas was needed to refuel the system.
Checking the operation of the equipment is done by connecting the device to the trunk. With insufficient filling with freon, cranes are frosted (this is the main indicator). If this does not happen, then you have filled the climate equipment correctly.
Air conditioning in a car is no longer a luxury. Most modern cars go off the assembly line with installed air conditioning systems. Usually, the level of freon is checked during maintenance. However, if you have a suspicion that it is time to refuel the air conditioner, you can’t do without preliminary diagnostics in any case ...
The annual natural loss of freon is about 15%. This means that once every 3 years, the air conditioning in the car should be refueled. Significant loss of cooling gas may indicate a leak in the pipe connections or corrosion in the condenser. It should be remembered that in the event of a refrigerant leak, it is first necessary to eliminate the causes of losses and only then charge the air conditioner.
If the air conditioning system after refueling works poorly, it may be necessary to diagnose the climate control system for a malfunction.
› How to refuel a car air conditioner with your own handsLEMANS RU
📹 Useful videos on the device and repair of cars you will find only here
The car air conditioner is a unit that creates and maintains a given microclimate in the passenger compartment. Car air conditioning, like any other equipment, requires timely maintenance. That is why, in order to maintain it in working condition, periodic refueling of the car’s air conditioner, cleaning of the air conditioning system, and a number of other procedures that prevent its failure are required. Those car owners who often use air conditioning, most likely, have already visited the service centers for its maintenance more than once, paying a certain amount of money (the price of refueling an air conditioner starts at 1000 rubles). However, you can save on this procedure about how to self-refuel the car air conditioner and tell in our article.
The principle of operation of the air conditioner
Before you start refueling the air conditioner in the car with your own hands, in order for the procedure to be successful, it is advisable to deal with the device and the principle of its operation. The system has three main parts:
Compressor;
- capacitor;
- evaporator.
The conditioning process is approximately like this:
Freon, circulates in a closed circuit, passing all 3 parts.
The air conditioning compressor compresses the gas and raises its temperature.
Then the refrigerant (already hot and under pressure) enters the condenser, where it cools and condenses (becomes liquid).
After that, the freon goes into the high-pressure circuit and is led to the expansion valve, where it is sprayed and enters the evaporator.
It is in the evaporator that the cooling process takes place, since there the refrigerant is evaporated, and as a result heat is removed from the air, and it is cooled.
In the circuit closure, freon again enters the compressor (in the form of cold gas) on the low pressure side, and there the process repeats itself back.
How often to refuel air conditioning in a car?
During the operation of the air conditioner, a small leak of freon occurs. The rate of such gas loss in 1 year can reach up to 15%. So, every three years, if the circuit did not depressurize, the machine must be charged with refrigerant in the air conditioner. And in the case when the car is already quite old, the natural leakage is even greater, so refueling may be required a year more often, but the refueling method will be similar.
When there is a large leak of freon, it does not make sense to refuel the car’s air conditioning, you must first identify the damaged area and fix it (this can only be done at a specialized service using ultraviolet light).
When the leak of freon is more than normal, then most likely:
Or the tubes of the air conditioning system through mechanical / corrosion damage have lost their tightness;
- either corrosion processes have appeared inside the capacitor.
What is freon in a car air conditioner?
Previously, R-12 fluorine-containing Freon was used to refuel the air conditioner, although it is more productive, but due to the fact that it is very harmful, it was banned in 1992 and replaced with R-134a refrigerant. Therefore, owners of cars with air conditioning produced before 1992, have to either refuel on their own, or also switch to a new type of freon. After all, although they work on R-12, refueling with chlorofluoride-containing gas is prohibited at service stations. So all new models of cars with automobile air conditioning are charged with R-134a freon. By the way, which freon in the automobile air conditioner of a particular system can be seen on the plate by raising the hood. Although it is difficult to mix up, after all, even the filling nozzles are different (in the tube under the R-134a it is higher and with a larger diameter). On the sticker under the hood, you can also see the rate of freon refueling in the car air conditioner.
The amount of freon in the car air conditioner
Before refueling the air conditioner with your own hands, it is advisable to determine exactly how much freon is in the car's air conditioner in order to calculate with the purchase the required number of cans. It’s already been found out that you can see the rate of Freon filling in the car air conditioner on the plate under the hood, where both the type of refrigerant and its amount in the system are indicated.
When for some reason the table is missing, then you can find out how much refrigerant you need from your car dealer or see the manual. For Russian cars, the refueling rate is usually around 600-900g. Although, in principle, accuracy by and large is not needed, because, as a rule, the system is refilled with its own hands, and not the air conditioner is completely filled. The car air conditioner is refilled either at the factory or after repair, when the gas is completely exhausted, and with scheduled maintenance, we can only refill with freon to the norm, when it can operate at full capacity. But with such a partial refueling car air conditioner we cannot know how many grams of freon are left. Therefore, the air conditioner in the car is refueled by the pressure displayed on the pressure gauge. Therefore, if you could not find out the exact numbers and determine the amount of freon in the car’s air conditioner, then follow the arrow of the device.
Since in garage conditions there is no way to find out the exact amount of refrigerant, it is much easier to determine how much freon is needed to refuel the machine air conditioner according to the pressure gauge.
Topping up oil when refueling the air conditioner
In the table of the amount of freon in the machine air conditioner there are always numbers and refueling norms for oil, but few people know how to add it, and why. Some drivers, when refueling the car air conditioner, are advised to always add oil. But an excess of lubricant often leads to a breakdown of the piston compressor, since the oil, passing through the unit together with gaseous refrigerant, burns up at the nodes. So what to do in this situation?
The answer is quite simple - it is better to use freon with the addition of oil to refuel the automobile air conditioner (such information is indicated on the can of refrigerant), since it is already dosed there. But if, nevertheless, a separate lubricant filling is provided, then polyalkylene glycol oil - PAG (in the middle photo) should be used. Oil is poured into the compressor through the crankcase (indicated by the arrow in the photo on the right).
Do-it-yourself air conditioning evacuation
Not all of them take this into account, but the evacuation of the air conditioner is also an equally important procedure, in addition to the norms for filling freon and the amount of oil in the system!
When less than 50% of the refrigerant is left in the car air conditioning system, airing and moisture ingress is inevitable. Naturally, the unit will be able to work, although not at all its potential, but, most likely, the compressor will fail, and corrosion will form on the tubes of the system, and then repair will cost much more than evacuation. A vacuum pump is required to remove atmospheric air and moisture vapor from the air conditioner.
To evacuate the air conditioner yourself, you will need:
Turn on the heater and warm up the car so that moisture condenses in the evaporator;
Connect the vacuum pump to the compressor fitting, and then, having unscrewed the nipple, turn the tap under it (counterclockwise);
Turn on the pump for 15 minutes, then close the valves and turn it off. Repeat the procedure several times.
After completing the procedure, you need to wait 2-3 hours, and only then you can refuel the car air conditioner.
Equipment for refueling a car air conditioner
Self-fueling an air conditioner requires both basic skills and a certain set of equipment. Therefore, to check the pressure in the system and the subsequent refueling of the automobile air conditioner, you need to purchase:
Metrological station;
- hoses;
- adapter with a tap, allowing you to connect to the system;
- a refrigerant cylinder of the appropriate type (R-12 or R-134a).
All the necessary equipment for refueling a car air conditioner with your own hands can be purchased at any car shop.
The standard magazine kit for refueling is connected as follows:
The cylinder with freon, on it there is a thread and a plane, which is pierced by a needle during the connection of the adapter (when such an adapter with a faucet is missing, you need to purchase separately).
The coupling allows you to connect through a tee, pressure gauge and hose.
The other end of the hose connects to a metrology station (purchased separately) to which another hose connects.
How to refuel and how to distinguish where is a fitting?
Air conditioning systems have two sides: low (shown by the red arrow) and high pressure (the blue arrow points to it).
The autoconditioner is charged to the low-pressure line, therefore, first of all, you will need to find the right fitting. To prevent refueling from the high pressure side, the inlet sizes are different. On some models, the nozzle caps are marked with the letters “H” and “L” or have a different color.
When unscrewing the tap of the low-pressure line, carefully wipe the cap itself and the pipe section with a rag to prevent dust or debris from entering.
Stages of self-fueling the car air conditioner
Regardless of the model of the car and the appearance of the nodes, the general instructions for refueling the car's air conditioner will be similar.
So, to fill freon into the car air conditioning system, do the following:
We clean the protective cap and the section of the low-pressure line from dirt, then open it.
We put a hose from the previously assembled equipment onto the filling nozzle.
The instructions for refueling autoconditioners include starting the engine and supporting 1,500 rpm. They need to be kept so that the compressor will pump freon along the highways. Therefore, at this stage, either need help, or you can put something under the gas pedal.
Turn on air recirculation in the cabin to the maximum.
We open the faucet of the low-pressure line by turning the cylinder with the refrigerant upside down, and slowly open the valve. The air conditioner starts to refuel (with the engine running).
Refueling the car air conditioner is accompanied by constant monitoring of the pressure gauge.
The pressure in the low pressure line should not exceed 285 kPa and ideally should be 10 units less. Exceeding the maximum allowable pressure can result in compressor failure.
To understand whether the system is being charged correctly, you can look through the window of the filter-drier - if there are no bubbles and a clear liquid is visible, then you are doing everything right.
As soon as cool air enters the cabin (about 5-8 C °), and the hose near the low-pressure fitting is as cold as ice, the filling procedure of the air conditioner of the machine can be completed.
How to extend the air conditioning service lines on a car?
To extend the performance of the air conditioner, you should follow simple recommendations for self-service:
Periodically wash the radiator of the air conditioner (condenser);
- in winter, call in a warm room and let the air conditioner run for 10-15 minutes, at least once a month.
As you can see, self-filling the car air conditioner is not difficult, and if there is no need to look for a freon leak or repair the air conditioning system, then you can do it yourself. Although, of course, in order to benefit from independent actions, you need to have all the necessary kit for refueling the refrigerant, because its cost will cost you the same price as refueling the air conditioner at the service station. Therefore, this procedure is beneficial to do with regular, every 2-3 years, maintenance of the air conditioner.
1 year
Even the most expensive and reliable air conditioning in a car loses its power over time. The first thing that is noticed at the same time is the time spent on changing the microclimate in the cabin. Finding information on how to refuel a car air conditioner with your own hands, as a rule, is not so easy. Therefore, most drivers solve this problem simply - they turn to a car service. But this is the most cardinal way to solve the problem. In this article I will try to help motorists and tell you how to carry out such a necessary process on their own.
To refuel an air conditioner, you need to understand how it works. It is very important to determine if the air conditioner really needs refueling. According to its purpose, the air conditioner can both cool the air and maintain a certain temperature in the cabin.
The fluid that circulates in the air conditioning system plays a key role in cooling. Despite the reliability of air conditioners, time takes its toll, and freon may soon leak. The normal annual loss is 15%, but if this figure changes upwards, then something should be done with the air conditioner. The standard time for filling the unit with freon is after three years of operation. But if the unit is old, refueling should be done more often. At any outcome, refueling is the same.
It does not make sense to refuel the air conditioner if any part of the system is damaged and malfunctions. If the problem is not very serious, you can fix it yourself, but when serious damage or breakdown occurs, it is best to contact a specialized salon.
Cold air circulating in the cabin returns to the system. This is due to the fan. Refill the air conditioner only when it ceases to function properly, that is, it ceases to cool the interior. But do not wait for a complete breakdown of the entire system or its failure. It’s best to carry out preventative refills that extend the life of your system. Such a refueling occurs every two years. You should also check the rubber seals, whose life is also limited. Due to changes in temperature and vibration, they can change for the worse.
Replacing freon not only helps the system cool. Since freon contains oil, its replacement allows you to keep all elements of the system in excellent condition. The service life of the device is significantly increased.
If refueling is done on its own, help like no other car manual can help. Or rather - instructions for refueling car air conditioners. 
Troubleshooting Freon Leaks
A strong leak of freon has its own reasons. You can identify them, but in view of the most common you can meet:
- Poor insulation of piping systems
- Damage to the pipes in the air conditioning system
- Capacitor Corrosion
Even if the car is equipped with climate control, this system will not help the driver find a freon leak. To find such a malfunction, the equipment needs a completely different one. 
A leak detector is a device that can detect air with freon even with its minimum presence. The sensitivity of such a device is so great that it can lead you directly to the place of leakage.
If there is no possibility to use the leak detector, then other devices can be used. Completely filling the system, an ultraviolet dye is added to the composition. 
Refueling technology should not be changed. Several times, turning the air conditioning system on and off, all joints and places of its action are illuminated by an ultraviolet lamp. If there is a leak, the places of disappearance or weathering of freon will be highlighted in yellow-green or fog of the same color.
Strong leaks in the car are best repaired by the service. At the same time, there is a chance to go through a climate control system diagnosis. Minor damage can be repaired by yourself. If there is a hole or crack in the system, it is closed with a small piece of metal tube. The diameter should correspond to the place being repaired. The tube is held with screeds or clamps. The edges are cleaned with alcohol and cleaned with sandpaper. Alcohol degreases the edges of the joints. The coupling halves are fastened with ordinary electrical tape, and after applying glue, they are fixed with clamps.
Which freon to use
In order to refuel the autoconditioner yourself, you need to decide on the type of freon.
The old R-12 was banned and replaced with the more modern R-134a. If your car was produced before 1992, then for it you need to look for the old and "forbidden" freon. To find out what freon is required for a car that was released between 1992 and 1993, a sticker on the inside of the hood will help. For more "advanced" drivers, it is not difficult to determine the type of freon for refueling simply by the appearance of the nozzle for refueling. The new freon is refueled in air conditioners with a high fitting with a large diameter. 
Also, ammonia is used to refuel car air conditioners. The very first air conditioner, which saw the light in 1929, used ammonia for its work. The development of refrigeration technology was severely inhibited due to the fact that the substance was unsafe for human health. Freon was synthesized in 1931. It was completely safe and the problem was resolved. Since then, up to four dozen freons of various types have been developed, which differ in their properties and chemical composition. The cheapest options have been satisfying for quite some time. However, their properties were destructive, so over the past 15 years they fell out of love.
The evolution of coolants is very closely related to ecology. One period of development of this type of industry was distinguished by the fact that at that time freon from cars was blamed even for the appearance of ozone holes. In 1987, a law was passed that prohibited the use of destructive substances. Therefore, the brand of freon R-22, which was the most popular, had to be replaced. Those refrigerants that are shipped from Europe now are less convenient because they are mixtures of various freons. However, each of the refrigerants increases productivity, eliminates fire, determines the pressure in the circuit.
An air conditioner improves ride comfort during the summer heat. Over time, any car air conditioner loses refrigerant due to damage to pipes and other parts. After reading the article, you will learn how to properly fill the air conditioner, what tools, substances will be needed and whether it is worth doing it yourself.
How does a car air conditioner work?
This device works on the principle of a refrigerator: the compressor compresses the refrigerant (freon), increasing its temperature. Hot freon passes through a condenser (analogue of a cooling radiator), where it cools and goes into a liquid state. Liquid gas enters the evaporator, which is also an analog of the radiator. The transition from a liquid to a gaseous state leads to a sharp drop in temperature, because of which the evaporator radiator is cooled to a negative temperature. The compressor fan draws in the outboard air and blows the evaporator around it, then drives the air into the cabin, lowering its temperature.
Air conditioner diagnostics
If the air conditioner starts to work worse, do the diagnostics yourself. Here is a list of the main steps for this:
- Checking the cabin filter.
- Inspection of hoses, tubes, condenser and evaporator.
- Checking the electric motor and fan blades.
- Belt check.
- Compressor check.
To check the cabin filter, it is pulled out and inspected. The clean filter is inserted back, the dirty one is replaced with a new one. Inspection of the condenser may require removal of the radiator grille. To inspect the hoses, evaporator or tubes, you need to remove the casing (this procedure is described in the car's manual). If you installed the car air conditioner yourself, read the instructions that come with it.
If refrigerant leaks through damage to the tubes, replace them whole or visit a specialist workshop for repairs. Do not use adhesives or sealants; they are unreliable.
If the radiators are damaged, replace them yourself or contact a specialist workshop. Check the belt tension and compare with that specified in the machine or air conditioner instruction manual. Start the engine, then increase the speed to 1500 per minute. Grasp the high-pressure outlet with your hand (a thick steel or copper tube is connected to it). If the compressor works correctly, then after 1-2 minutes the output will heat up and your hand will become hot. If your hand burns, the compressor must be repaired or replaced. If a little warm - there is too little refrigerant in the system. Grasp the cold pressure outlet to which the thin tube fits. After 1-2 minutes, the hand should freeze to pain. If not, the system has a large refrigerant leak and needs serious repairs. It is also necessary to check the condition of the fan and replace it if necessary. This procedure is described in the manual of the car or air conditioner.
Preparation for refueling the air conditioner
Before you start refueling the air conditioner with freon yourself, you should understand that this is a very complex process, with a lot of nuances, so it is difficult to do it right. In addition, normal equipment for working with freon will cost much more than the services of a master. If you are determined to refuel the car air conditioner yourself, carefully study its instructions. Because actions that are suitable for one air conditioner are not applicable for another. Typically, air conditioners are charged with freon once every three years. If there is a leak, then you will have to refuel it often.
What you need to refuel an air conditioner
For work you will need:
- container with freon;
- pressure regulators;
- hoses for connecting to an air conditioner;
- adapters;
- vacuum compressor.
Freon Choice
Until 1992, car air conditioners were run by R-12 freon. It is more effective in terms of cooling, is inexpensive, but harms the ozone layer. After 1992, any car air conditioner is made only for R-134a gas. There are other modifications of freons for air conditioners. It is impossible to mix different types of freons, this will damage the evaporator and condenser. There is a sticker on the inside of the hood lid that indicates which refrigerant is charged into the device. The average cost of a spray can (500 grams) of refrigerant is 1,000 rubles. The average cost of a cylinder (13.6 kg) is 8 thousand rubles. If there are leaks in the pipes or radiators whose size does not exceed 0.5 mm and, for some reason, you cannot contact a specialized workshop, use sealants for the air conditioner. The average cost of a bottle sealant (13.6 kg) is 15 thousand rubles, the average cost of a can (500 grams) is 2000 rubles. Do not use sealant often; it is better to repair damaged parts on time.
Selection of Pressure Regulators
The industry produces three types of pressure regulators:
- for refueling through a high pressure fitting;
- for refueling through a low pressure fitting;
- universal.
The cost of regulators starts from 2 thousand rubles. They are used for all types of freon and sealant. For pressure regulators you will need valves, tees, hoses and other devices. The average cost of these devices is 4 thousand rubles.
Other tools
To refuel the air conditioner with your own hands, they often purchase fully-equipped kits that consist of:
- spray bottle with 1 kg of refrigerant;
- valve;
- tee;
- pressure gauge;
- hose with fitting.
The average cost of such a set is 4 thousand rubles. If the air conditioner has not worked for a long time, it will be necessary to remove air from it. A vacuum pump costs 3–6 thousand rubles.
How to refuel the air conditioner yourself
To charge the car air conditioner with your own hands, remove the rubber or plastic plug from the low or high pressure line (depending on the equipment you have). Assemble the refueling device and connect it to the fitting. Start the engine and set the RPM to 1500 per minute. Open the valve and refuel for 5 minutes. Stop the engine and close the valve, and after 5 minutes, look at the pressure gauge. If the system pressure is below normal, repeat all operations. Do not overpressure, this will damage the air conditioner. In more detail, the procedure for refueling your particular air conditioning system model is described in the car or air conditioner instruction manual.
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