General issues of the operation of the air conditioner, we examined in the last issue of the magazine. Now let's talk about the role of the most important devices in these systems.
In an air conditioner with a thermostatic control valve, the refrigerant from the condenser enters the filter drier, which has several functions: save a certain amount of refrigerant, clean it of impurities, and remove moisture. Water vapor adsorbs silica gel granules placed in a cloth bag. God forbid it to break: the flow of refrigerant will spread the granules to all corners of the units and pipes, threatening clogging. If this happens, you have to open and rinse everything and everything.
When replacing any element of the system, it is recommended to simultaneously change the filter drier. There is no mistake! The purchased filter should be with plugs on the fittings, otherwise the silica gel has probably already been saturated with moisture from the atmosphere - and is good for nothing. A brand new filter drier costs between $ 60 and $ 90.
Some filter driers have a window to check the status of the refrigerant. In the reference literature, you can find explanations for the bubbles, the cloudy, foamed refrigerant, but for an inexperienced person this information is often superfluous: often after a few minutes of operation of the air conditioner, the bubbles disappear and later may reappear. After all, there are many factors of influence - from the system’s operating conditions to weather conditions. Therefore, if the air conditioner is in good condition by all other indications, there is no need to panic. Modern filters, as a rule, without such windows, and a serious diagnosis of the air conditioner is carried out in the service.
In an expansion tube air conditioner, refrigerant purification and moisture take-off take place in a battery located between the evaporator and compressor. Almost everything that has been said about the filter drier is also true for the battery (including the problems of refrigerant drying). And the specific task of the battery is to turn the refrigerant into a gaseous state, because after that it enters the compressor, and it is not designed to work with liquid - and it will probably break.
The most important element of any air conditioner is the compressor. Its malfunction produces a characteristic noise, which has two main sources: wear on the pulley bearing or breakdown of the compressor pump part. In the first case, noise is heard even when the compressor is off. Do not pull for repairs: if the bearing is jammed, it may damage the pulley, pressure plate and compressor shaft. The last is a sentence to the unit, it will have to be changed. If the compressor is driven by a separate belt, it is better to remove it and so move to the place of repair.
Repairing the pump part of the compressor is even more difficult. Compressor manufacturers supply only gaskets and gaskets for spare parts; piston sets do not exist. Another master can create anything. For example, a connecting rod with a piston will be thrown out of a bullied cylinder - let the rest work. True, irreparable vibrations will immediately appear, but not every owner will notice this!
The new compressor will cost at least $ 450-650. But just by replacing the problem is not solved. While there was a faulty compressor in the system, the refrigerant smashed metal particles and other garbage through it - if all this gets into the new unit, then he can’t live. So the system needs to be flushed. But how, where and how?
About solvents or gasoline is out of the question - rubber hoses will suffer. Only a special solvent! It is not necessary to disassemble the system - this is a huge and risky job: you can damage nuts, fittings, etc., which we have already talked about. The best option is CIP using a washing unit. The solvent enters the line break, dirt accumulates in the installation filter. One hour is usually enough to remove deposits. After that, in a system with a thermostatic valve, the filter drier is changed, and in the variant with an expansion tube, both the tube and the battery are changed.
Evaporator is an important element of the air conditioning system. Tucked under the dashboard. Atmospheric air containing water vapor is cooled here, moisture condenses on the tubes and ribs. Road dust sticks to a wet evaporator, this “coat” disrupts heat transfer - and the efficiency of the condenser decreases. That is why a car with air conditioning must be equipped with a cabin air filter. The latter, of course, is also clogged with dust - you need to change it regularly. Most often, it is placed under the plastic lining of the windshield or behind the glove box in the cabin. But a clean filter is not everything. The enclosed space around the wet evaporator is a great place to grow bacteria. Confirmation of an unpleasant smell in the cabin.
It’s not for nothing that aerosol cans for treating an evaporator are now so popular - but the owner acts blindly, and even it is difficult to clean the evaporator separately from the machine! By the way - where will the washed mud go? Of course, it will go into a thin drain pipe to drain the condensate. Clogged up - here's another misfortune.
Manufacturers do not even hide that the main goal of this "aromatherapy" is to give the air in the cabin a pleasant smell. It often happens that a highly contaminated evaporator still has to be changed.
In conclusion, an important point. After replacing any node, the air conditioning system must be evacuated. In service, this is done with a special pump. Without this operation, there can be so much excess moisture in the air conditioner that silica gel will not help - and the service life of the system elements will be significantly reduced.
Filter drier. Aluminum alloy housing. Inside are a filter element and a bag of silica gel. The operating conditions of this device are by no means greenhouse. Under the hood, most cars are pretty crowded, so the filter drier is often placed behind the front bumper next to the condenser, in the realm of dirt and corrosion. Ulcers form rather quickly on the casing, and there, one step before refrigerant leakage. The fasteners of the aluminum filter are steel: if there are no insulating gaskets between dissimilar metals, then the “collapse” is sharply accelerated.
Battery. Aluminum alloy housing. In a system with an expansion tube, it must be located between the evaporator and the compressor; After all, the most important task of the battery is to transfer the remaining liquid refrigerant into a gaseous state, since then it enters the compressor, which is not designed for pumping liquids. If liquid gets into it, breakage is possible. This is especially dangerous for a reciprocating compressor. As for the other functions, they are the same as the filter drier.
Expansion tube - a device with a strainer and a nozzle inside (not visible in the photo). Light - a new product. Nearby is a tube covered with deposits of wear products - chips, metal filings, etc. This sample was extracted from a system in which the compressor part of the compressor had long been in need of serious repair.
The heart of the air conditioner is a compressor. There are blade, spiral, piston units - with constant and variable performance. The compressor is usually mounted at the bottom of the engine block and is driven by a V-ribbed belt from the crankshaft pulley.
The most common are reciprocating compressors, often with five, seven, ten cylinders. Very effective, but demanding on the purity of the refrigerant is no less than a piston engine on the purity of air and fuel. The piston design does not tolerate liquid coolant - water hammer immediately breaks the details. But the vane compressor for pumping liquid is not designed.