How to check the air conditioner? Identification of the causes of partial malfunction of air conditioning equipment.

Express analysis of compressor oil

In order to carry out this procedure, it is necessary to take a sample of oil from the freon circuit, compare its color and smell with a sample of good oil, and also conduct an acidity test.

So, the dark color of the oil and the smell of burning indicate that the compressor has overheated.
The cause of overheating may be:

refrigerant leakage from the freon circuit and operation of equipment without refueling;
increased pressure in the system due to contamination of the radiator or deterioration of fan airflow (incorrect operation of the board);
failure of the fan itself;
lack of a winter air conditioning kit for operation at sub-zero temperatures;
operation of equipment in heating mode at low negative temperatures.

As a result, the oil loses its properties.

A greenish tint to the oil means the presence of copper salts, which may be due to excess moisture in the freon circuit, then the oil acidity test will be positive.

If the oil is clear, then the compressor is working absolutely properly.

Using a compressor oil acidity test, you can quickly confirm or refute concerns that were determined after analyzing the color of the oil. The analysis is carried out using special equipment.

Pipes in oil

In addition to the refrigerant, the air conditioning system (cold and hot circuit) contains a small amount of oil (approximately 50 to 200 grams). It is needed to lubricate the air conditioning compressor and it also “circulates” through the system.

If the air conditioner is not working, inspect all the pipes, if there are oil leaks somewhere - most likely, oil is oozing here and this is where freon (refrigerant) is escaping. It needs to be fixed - repaired.

Now let's watch the video version

In conclusion, I would like to say that it is not so difficult to test the air conditioner yourself for performance, read and use it. I think my materials were useful to you, sincerely yours AUTOBLOGGER

Checking the tightness of the freon circuit

Loss of tightness of the freon circuit, as a rule, leads to disastrous results. It can be caused by various reasons. The danger is that the compressor, cooled by the refrigerant, overheats as a result of the reduction in the amount of gas. As a result, an increase in the temperature of the compressor, a disruption of the lubrication system, an increase in friction of internal parts, and an increase in current strength.

You should be alert to the following signs:

icing on the taps of the external unit;
darkening of the compressor insulation;
presence of greasy oil stains;
false activation of thermal protection;
dark colored oil;
positive acidity test results.

If you detect the problem in time and prevent the refrigerant from leaving completely, you can avoid complex repairs at a service center. Therefore, we once again insist on timely diagnosis.

Air conditioner pressure sensor - operating principle and how to check for malfunctions +

The air conditioner pressure sensor, despite its miniature size, determines the performance of the entire system. Let's figure out where this device is located, study its operating principle, think about what problems we might encounter, and outline ways to solve them.

First, you should familiarize yourself with the operating principle of the entire split system, and only then will you be able to correctly assess the role of each node separately. The operation of a car air conditioner can be compared to the operation of an ordinary household refrigerator, although its design is somewhat different from this unit. Essentially, a car air conditioner is a sealed container filled with special oil and freon.

Freon for car air conditioner

After pressing the power button, the electromagnetic clutch is activated. Under the influence of a magnetic field, the pressure disk is attached to a pulley, which begins to move using a special belt. This is how the compressor begins to function. It strongly compresses the freon, and the hot gas flows through the pipeline into the condenser. The latter device includes a fan that turns on simultaneously with the compressor and cools the freon.

A gaseous substance after cooling turns into a liquid state. The mixture is filtered in the receiver-dryer, then it moves to the evaporator. A thermostatic valve is installed on the pipeline. Essentially, this device is an automatically adjustable throttle. Through this valve, freon enters directly into the evaporator, where it is greatly cooled, and the icy air is blown into the vehicle interior. Next, the freon again enters the compressor, and all operations are repeated in a circle.

Thermostatic valve

But special devices monitor the correct operation of the system. The function of the low pressure sensor of the air conditioner is to automatically turn off the split system if there is insufficient amount of freon in it. Sometimes there may be no cooling mixture at all. A lack of freon threatens air leaks due to very low pressure inside.

This process is also extremely undesirable. The high pressure sensor, on the contrary, blocks the operation of the compressor if this characteristic exceeds the permissible values. Excessive pressure can cause physical destruction of the system. In addition, the functions of the sensor include the responsibility of periodically turning on and off the radiator fan.

The system is also equipped with a temperature sensor that turns off the system as soon as frostbite begins. Otherwise, the evaporator will be crushed by ice. So we have no right to underestimate the role of even such small components and must monitor their condition so as not to fall victim to expensive repairs later.

Features of low and high pressure sensors

Today, there are various modifications, but the operating principle of air conditioner pressure sensors remains the same. As soon as the pressure reaches critical values, the device sends a corresponding signal to the electronic engine control system and the pump automatically turns off. Along with the compressor, the fan stops functioning.

Air conditioner pressure sensor

The simplest models interrupt the compressor control circuit as soon as the pressure value becomes emergency (less than 0.17 bar for a low pressure sensor and more than 25–30 bar for a high pressure sensor). However, this device can operate at several values. 4-contact devices are popular, which in addition react to intermediate pressure, for example, 16–17 bar. This value is considered the most acceptable for air conditioner operation. As soon as the pressure in the system reaches 16 bar, the sensor gives a corresponding signal and the fan turns on.

More modern devices are used in conjunction with an electronic climate control unit. They transmit a signal about the current state of refrigerant pressure, and the control unit “decides” what to do next. This makes it possible to create multi-stage control of fan operation.

Electronic climate control unit

Air conditioner high pressure sensors differ in external and internal threads, depending on the make of the car. They also have an unequal number of contacts. The types of connectors are also different. There are universal models, but they can only be installed on universal receiver dryers. A high pressure sensor is installed between the right shock absorber strut and the air filter.

How to spot a faulty pressure sensor?

Now let's take a look at the malfunctions of the air conditioner pressure sensor, how to check it and, if necessary, replace it. Basically, failure or incorrect operation of this element can be caused by elementary contamination or mechanical damage. So after the first signs, be sure to check the condition of the connectors and wires. Any cracks, traces of moisture and corrosion are unacceptable. Don't forget about computer diagnostics.

Computer diagnostics of the air conditioning system

You can understand that you need to visit a car service center or get under the hood yourself by looking at the following signs. Firstly, the operation of the compressor is disrupted; it can turn on at excessive pressure or function even without freon. Sometimes the compressor does not turn on at all. Secondly, there are interruptions in the operation of the fan. And the entire air conditioning system is functioning unstable.

Replacing the sensor and preventing breakdowns

If this element fails, it is necessary to urgently replace the air conditioner pressure sensor. Of course, you can turn to specialists for help, but this procedure is simple and can be done independently in a garage. We will need a key for "14". It is advisable to have an inspection hole, but you can also use a lift.

Replacing the DDC

We turn off the engine, since this operation is carried out only on a car with the ignition turned off. Move the plastic bumper protection a little and look to the right, you will see this sensor. To dismantle it, you need to lift the latch on the plug and remove the wires connected to it. Now we unscrew the device with an open-end wrench. Thanks to a special safety valve, there is no need to worry about refrigerant leakage. We screw a new device into the free space, connect all the wires to it, return the protection to its place and enjoy comfortable movement in your favorite car.

There is another way to get to this sensor without using lifts and inspection holes. You just need to remove the front bumper. But the method described above is simpler to implement. If the replacement is quite feasible on your own, then checking the air conditioner pressure sensor should be entrusted to specialists, because this will require expensive equipment and it is not practical to purchase it for home use.

Removing the front bumper

For prevention, be sure to turn on the climate control in cooling mode for at least 10 minutes, even in winter. It is enough to repeat this operation once a week. With the onset of frost, first warm up the car thoroughly and only then start the air conditioning. Touch the torpedo, it should not be cold. When flushing the capacitor, you need to act very carefully, since the thin ribs of its cells are easy to deform. Use only high-quality refrigerant and choose a car service seriously. Failure to comply with refueling technology will lead to very serious problems with

Source: https://carnovato.ru/proverit-datchik-vysokogo-nizkogo-davlenija-kondicionera/

Monitoring the absence of moisture in the freon circuit

Moisture entering the freon circuit often occurs due to incorrect installation. The danger is that such a breakdown has no visible signs until the moment when the compressor fails. Removal of moisture is possible only by service center specialists.

Avoid breakdowns, call us tel.. Our technicians carry out regular diagnostics of devices, and you won’t have to spend money and time on repairing a failed air conditioning compressor or replacing it altogether. We save your money and work efficiently!

How to check the air conditioner in a car with your own hands

You decided to buy a car, chose one that suits your pocket, got in and drove it. It’s hot outside and we decided to check if the air conditioner is working, and the seller starts telling you that the air conditioner is working, you just need to refill it. But you absolutely cannot believe such words. What if there is a leak or some other problem. You counter the owner’s words with the fact that it’s hot outside and you’re suffering from driving without air conditioning - you would fill it up and drive normally if that’s the problem, according to you.

When they try to sell you a car with a problem air conditioner, this is exactly the song from the seller. There are two reasons for a faulty air conditioner: a leaky system, a faulty air conditioning compressor pump. Our advice is that when buying a car with a non-working air conditioner, be sure to reduce the price of its repair. Even if they assure you that everything is fine, you just need to refill the freon. Don't be fooled.

There are leaks in the radiator and evaporator. Leaks appear in the radiator from stones falling there, from the fact that dirt gets there and rots. As for the evaporator, to get to it you will have to remove the entire dashboard of the car. The service estimate for repairing the evaporator is 12 hours!!!

If you still want to buy a car, but the air conditioner does not work in it, our advice is to go to a service station and have them make a vacuum in the system with a special device, so that you can immediately understand the reason and how much it will cost you to repair the air conditioner. Also don't forget to check the compressor pump.

In winter, you can check the air conditioner by opening the hood and checking whether the compressor pump rotates; if so, then in 85% of cases everything is fine with the air conditioner. But it’s still not a fact that if the pressure in the system is less than required, the air conditioner will not work. You can also smell the air from the deflectors; it should be frosty (fresh).

The main sign that the system is working is to turn on the air conditioner and feel the supply and return pipes. One will be hot and the other will be ice cold.

An indirect sign of a working air conditioning system in a car is the fan turning on; it will constantly work.

A very important fact! If the cabin filter is not changed in time, the evaporator becomes dirty and a graveyard of bacteria appears on it, which decompose and stink. Another indirect sign is to open the cap, as in the photo, and press the nipple; if it clicks, then the system is most likely sealed.

This method of checking the air conditioner in a car is suitable for absolutely any model and brand: Renault Logan, BMW E39, Opel Astra, Ford Focus 2, Accent, Citroen C4 and others. The most important thing when buying a car is to check the air conditioning according to the points listed above.

Let's move on to diagnostics

So, we have identified the most important components of the system and are now starting independent diagnostics. Even if you have no previous experience of such work, it can be quite effective. We turn on the air conditioner and wait for the noise of the compressor. We touch the metal part of the return line with our hand. In 10-15 seconds you will feel your hand starting to freeze in the literal sense of the word.

After each switching off/on of the compressor, your hand will feel a new influx of frost.

Carefully touch the metal tube connecting the compressor to the radiator. As a rule, it is either warm or quite hot if the temperature outside exceeds at least 20°C. We check the condition of the thinnest line that leads to the radiator from the compressor. It is bad if it is very hot, because this is a sign of contamination of the system, either oversaturation with freon, or a broken fan.

If such actions do not lead to one of the described effects, you need to contact experienced car air conditioning technicians. In this case, you will have to measure the pressure in the system - it is possible that we are talking about a refrigerant leak or other, much more serious malfunctions.

Please note that the air conditioner may have been charged right before sale to check.

In such cases, a careful inspection of the pipes with their attachment points, the receiver-dryer, the compressor, and the air conditioner radiator will help. If there are traces of fogging, oil drips, or traces of dirt, then you should be wary of freon leaking from the system.

Step 4: Checking the air conditioner before installation