How to repair the air conditioner

Repairing the air conditioner yourself: diagnosis and troubleshooting.

Air conditioning equipment creates a comfortable atmosphere in the house and makes it more comfortable. But sometimes it breaks down at inopportune times, for example, in summer or when the warranty has already expired. Some malfunctions of the air conditioner can be easily fixed with your own hands. But before you take up the matter, you need to answer yourself two questions. Firstly, if you have a sufficient technical knowledge about the device of such units; secondly, what caused the breakage. If everything is alright with the first point, then we move on to the second one. The causes of split-system’s breakdown can be divided into three groups: manufacturer’s defect, low-quality installation and wrong exploitation. That is why it is so important to define whether it is possible to fix an air conditioner by yourself or you will have to apply to a service center.

The system of automatic malfunction diagnostics

The first thing to do is to make sure that the air conditioner is really broken. Luckily, in modern models you will be informed about many problems by inscriptions on the display or blinking of colored indicators. Having opened the instruction it is easy to decode, where exactly the failure took place. Detailed information about the codes is given only to authorized service centers, but the basic data is also available to ordinary users.

Normally the light will flash a programmed number of times based on the error detected. Standard fault codes (number of sensor signals):

1 blinks once – indoor unit thermistor is not working. 2 – Outdoor unit thermistor is not working. 3 – The unit is running both cooling and heating at the same time. 4 – overload protection is off. 5 – the cable and communication circuit between units may be defective. 6 – power consumption has exceeded the norm (check the power transistors). 7 – voltage in external unit has increased. 8 – fan motor is defective. 9 – running valve does not work. 10 – thermistor is out of order and does not control the temperature of compressor case.

Before operation, you should carefully study the instruction manual of climate control equipment

If conditioner does not turn on, and at the same time LED’s are not blinking, then most likely the control printed circuit board is out of order. When all the LED’s are blinking, it means that the control board program settings have malfunctioned because of the power surge, and you need to reprogram it.

Each model has its own program settings code, but this is also known only to authorized service centers. You can find the error codes on the Internet by brand name and try to reprogram the board yourself.

Diagnostic Sequence

Before starting any repair or preventive work it is necessary to carry out a detailed diagnostics of the climate system, to identify the cause of the problem, to assess the upcoming labor costs and the cost of necessary components or auxiliary means. The competent check will help to avoid erroneous conclusions, multiple, expensive and long term restoration of the unit working capacity.

The sequence of diagnostics includes checking:

  1. The presence of mechanical damage;
  2. Unit fasteners;
  3. Clamping of contact connections of its electrical equipment;
  4. Condition of air filters;
  5. Cooling/heating mode;
  6. Indication of modes;
  7. Functioning of mechanical louvers;
  8. Temperature of air at the evaporator outlet;
  9. Pressure in suction/discharge system;
  10. Tightness of all connections and drainage system.

The air conditioner does not turn on

Whatever the make or model of the unit, the reasons will be the same:

  • The electrical part. Either the air conditioner is not connected to power, or its control board has failed, or the communication between the units is broken.
  • The remote control or receiving module on the indoor unit is broken.

If the receiving module fails, the unit does not respond to signals from the remote control

  1. Protection system is activated and generates an error.
  2. Worn out parts. In the simplest case you will be helped by changing the batteries on the remote control, checking the plug and turning off the air conditioner for one minute. Check to see if the time is set on the off timer. Sometimes conditioner doesn’t work or refuses to execute remote control commands correctly because of wrong switching of signal and power wires between units. Later it can cause defects of control board parts. That’s why in case of such problems it is necessary to re-commut the wires as soon as possible in order not to change or repair the board later.

The device switches off after working for 5-10 minutes

There are several reasons for this

  • The room has already cooled to the set temperature;
  • Dehumidification” mode is activated;
  • Compressor overheats;
  • Control board is defective;
  • protection relay is out of order.

Let’s analyze why overheating of compressor is possible. First of all, let’s check if the radiator of external unit is not clogged with dirt. This interferes with the normal heat removal, the compressor starts to overheat and the system shuts it down. Preventive cleaning is the first thing to do in this situation.

If the air conditioner has recently been charged with refrigerant, the balance in the evaporator and condenser circuits may well have been disturbed, so the compressor began to work with overloading. After measuring the pressure it is recommended to bleed off the excess of refrigerant.

It is not excluded that the cooling fan of the outdoor unit is broken (rotation speed is lower than the preset rpm). Overheating is also possible due to clogged capillary tubes during installation. Probably one of them will need to be replaced. This can also be caused by a clogged filter drier due to contamination. If this is the case, the filter must also be replaced.

Condensate is dripping from the indoor unit. Fixing leaks

During the summer, the condensate collection tank often overflows. To avoid dripping from it, it is necessary to drain the water that has accumulated there more often. If the cause is frosting of the heat exchanger, it can be insulated with any thermal insulation material. If there are leaks in the places where the connectors are fastened, it is obligatory to tighten the nuts, and the joints are treated with sealant. Do not apply too much force when tightening the nuts, so as not to break the threads!

Probably, a drainage pipe between a drain pan and a place of a drain is clogged. It is necessary to de-energize conditioner, wait 10 minutes, then disconnect plastic pipe and clean it manually (by blowing or with the help of thin wire). This is the most widespread reason of water appearance. But there are others, such as:

Improper installation of the drainage system (it is too long, poorly secured, the hose is backed up);
mechanical damage to the body, drainage tray or other internal units.

If the drain pump is broken, it must either be replaced or repaired. The raised hose should be bent at the proper angle to allow water to drip downward. If a freon leak is suspected, see “Air conditioner starts but does not operate efficiently”.

If the drain pipe is clogged, water starts dripping from the indoor unit

Unpleasant odor

The filters should be cleaned once a month

There are several reasons when a musty or unpleasant chemical “odor” comes out of an air conditioner. Let’s consider the main ones:

  • The smell of burning indicates a fire in the wiring. In this situation, you need to immediately de-energize the unit and call a specialist.
  • Smells like plastic. Usually this means that split-system is made of cheap low-quality materials. This smell is difficult to liquidate even with the help of specialists.
  • The unit “smells” of dampness or mold. This means that colonies of pathogenic bacteria or fungi have formed inside. To destroy them, you need to buy any pharmacy antifungal agent, dilute it in water and treat all internal parts.

Do not forget to clean internal filters, otherwise they become breeding grounds for bacteria.

Abnormal sounds

In order to define the reason of “incorrect” sounding of split-system you should be experienced in it. But it is available for usual user as well.

  • Uneven noise during the work of outer block. It occurs, if you do not clean it from dirt in time. It is especially noticeable if the dust and dirt is unevenly deposited on the fan blades. They become unbalanced and the characteristic hum is ensured. Sometimes the noise appears after one of the blades is damaged. To get rid of it, you should clean the fan of the external unit or replace it.
  • Clacking. In this case, either the automation does not work properly, or it is triggered by the malfunction of internal parts.
  • Gurgling. Such sounds do not always mean a breakdown, but you should not ignore them. For example, sometimes, when air gets into the drain tube, the air conditioner starts gurgling because of the condensate that did not drain out. The decision: to straighten a tube at the right angle. Gurgling appears when the system becomes clogged – when air enters in place of freon.
  • Squelch. This sound is characteristic for a normally functioning air conditioner. The reason of the increased noise is sometimes poor quality of fixing of parts and blocks of the unit. For its elimination it is necessary to tighten tightly all connections and fasteners of structural elements of the system and pipes. The outdoor unit is aligned horizontally and sagging hinges are fastened together.

Inefficient operation

This is one of the most common malfunctions, especially noticeable during the hot season. The air conditioner consumes electricity, but does not provide the desired temperature. Possible causes of low efficiency:

  1. Clogged air filters. They look like a small flat or drum-type mesh under the front panel of the unit, and it is through it that air enters the air conditioner. The filters collect all the dust in the house and protect the indoor unit radiator from it. To clean them is rather simple – to remove and rinse under flowing water, then to dry and to put back. The procedure is done every two to three weeks, and if there is a lot of dust and soot, then even more often. Otherwise the radiator blowing speed will decrease, and it will cease to provide the necessary temperature. Disruption of the cooling system, in turn, will lead to freezing of copper pipes. After shutdown, frozen ice will melt and water will drip from the air conditioner. In case of heavy clogging of filters, the dirt will penetrate into drainage system too, and water will flow out almost in rivulets. And all this mess can be cleaned only with the use of strong chemicals. Important! The maximum number of washes filter – 6-8 times! Then it loses its performance qualities. This is what a very neglected air filter looks like.
  2. Dust on the impeller of the indoor unit. To fix the problem, you need to remove the panel, and remove the dust from the impeller.
  3. The heat exchanger of the outdoor unit is clogged. If the dirt, dust, lint or hair from the street gets into the outdoor unit, the load on the compressor increases, it begins to overheat and can fail completely.
  4. Freon leakage. It is necessary to know that it happens even in the case of the most professional installation, because of the flattened connection between the units. And this leakage should be regularly (once in two years) compensated by topping up with the refrigerant. If it is not done, the level will fall to a minimum value and the compressor can jam because of overheating. Since the price for a new one is half of the cost of air-conditioner itself, it should not be allowed. In order to define whether the volume of freon has decreased or not, it is enough to have a closer look at faucet connections of an external unit, there is no ice or hoarfrost there. Another indicator would be poor air cooling. In addition, even a small crack after the flare wire can cause a freon leak.
  5. Evidence will be leakage of oil under the faucets, darkening of the insulation. If you see these warning signs, the best thing to do is to turn off the unit and perform troubleshooting work.
  6. Non-adapted to winter conditioner. Many models, especially from Asian suppliers, where the temperature in winter does not fall lower than +8, are not adapted for work in conditions of severe frosts. And if you use a function of winter heating with non-adapted model, it will essentially reduce a life-time of your compressor. As a result there is a cold plug, which prevents condensate from flowing down when switching from heating to cooling mode. The problem is solved by installing a winter kit for heating and warming up the drainage system.
  7. Frosting of the outside unit. It happens, if a split unit is switched on heating at a high humidity and subzero air temperature. If it is not equipped with auto-defrost system, you should switch it on in a cooling mode for a while. Then defrosting will be provided by warm air moving outside. In general, it is not recommended to switch on the unit at temperatures below 50 F (10 C), because the oil inside the compressor gets thicker, which increases its wear and tear.
  8. Improperly selected capacity of the air conditioner, so it does not cope with the area of the room. In this case, only replacing the equipment with a more powerful one will help.
Fixing the air conditioner. Inside view

Cleaning or replacing the filter

Filters in air conditioners are divided into two kinds:

Coarse filters – present in all models and serve to protect the “organs” of the air conditioner from dirt and dust. They are located under the front panel and look like a fine mesh net made of plastic. There are two ways to clean them: with a vacuum cleaner by lifting the front panel or by removing the filter itself and rinsing it under water yourself. Don’t forget to completely dry it after the procedure.

Rinsing the Filter

Insufficiently dried filter can cause the further damage of the whole air-conditioner

Fine filters are all other types of filters found. They are more delicate in their structure, and have different functions (antibacterial, adsorptive, antioxidant, etc.). At the end of their service life, they are usually replaced with new ones. They must not be washed.

How to disassemble the conditioner

Disassembling of any unit follows the same scheme, that is why this way is universal. At first, stock up with the following tools:

  1. screwdrivers of all types;
  2. Allen screwdrivers;
  3. a soldering iron;
  4. a cleaner.

It is not necessary to remove the indoor unit from the wall for simple cleaning. Step-by-step instructions:

  1. First of all, the device is de-energized.
  2. First remove the outer panel. Under it there are two bolts covered with a fuse, and they must be unscrewed.
  3. After that we unclick the two latches and remove the frame. The upper panel is usually dirty and should be washed.
  4. It is necessary to take out the blade that directs the air masses and remove the lower panel of the indoor unit from the latches.
  5. After that the wires are disconnected (to avoid confusion it is better to draw their location in details).
  6. Then the brackets are pressed and the body of the electrical unit and transformer are taken out.
  7. To dismantle the drain and the output hose, the three supporting fasteners are squeezed out.
  8. Then the supporting bolts of the electronic motor are unscrewed, the radiator is gently lifted off, and the motor support is removed.
  9. After that, the blades and the motor, located in a special cell, are removed. To prevent the radiator from accidentally falling down, it can be put back in place.
  10. Then you must remove the heat lock, which is located on the friction wheel mounting bolt with the rim of the motor. This is quite difficult! To avoid accidental burning of the rubber part that transmits power, it is necessary to heat the bolt head with a thin soldering iron, trying to unscrew it in the process of soldering. After carefully separating the blades from the motor part, dusty and moldy parts are cleaned with a special cleaner.

How to remove the air conditioner

To disconnect, the first thing to do is to stop the supply of working fluid, turn off the air conditioner and drain the already filled fluid from it. After that it is necessary to disconnect the unit from a network and turn off the drain. Then the pipes supplying the liquid are removed, and the conditioner is finally removed from the wall. You can read more about this process in the article “How to dismantle an air conditioner with your own hands: instructions, video”.

Repair of the radiator with their own hands. For this you will need:

  • a powerful soldering iron (not less than 250 W);
  • solder;
  • rosin;
  • iron filings;
  • cryolite;
  • sodium sulfate;
  • two activators for flux – lithium chloride and table salt.

To begin, the conditioner is dismantled and de-energized. Then the cover is lifted, filters are removed and about one and a half liters of water is poured over the radiator. If it does not come out through the drainage tube, it means that there is an inner leak.

After locating the leak, it is dried, cleaned and degreased. In the case of a copper radiator, after fluxing, tin is applied, heated, and you can proceed to solder.

Water is again poured into the radiator to check the integrity.

If it is aluminum, an iron rosin substance is applied to the cleaned, degreased and dry (!) surface and the part where the solder is to be soldered is rubbed with a red-hot soldering iron. When rosin begins to flow, the part is fastened in the soldering zone with solder made of tin and lead, with the addition of iron filings.

Check of compressor performance

Changing filters, fixing leaks or topping up the air conditioner are the first steps when the refrigerant leaks, the insulation or oil darkens. But sometimes these measures are not enough, and more thorough diagnostics of the compressor is needed. And based on its results, it may turn out that the compressor needs a more serious repair. There is an express oil diagnosis for this purpose. To make a sample, you will need a test tube, a hose and a container for the liquid. The next steps are as follows:

  • turn off the machine;
  • wait for the oil to flow down the walls of the pipe;
  • connect a hose with a tap to the service port and dip the free end into the prepared container;
  • open the tap and collect the oil;
  • let the oil stand and pour it into a test tube.

If the oil has darkened and has a smell of burning, the compressor has overheated. Causes could be: refrigerant leakage, clogged external unit, deterioration of fan blowing, lack of winter kit.

The greenish color indicates the presence of copper salts in the oil. This means that moisture has entered the freon circuit. The danger is that it does not manifest itself in any way, and then the compressor fails. Compressor repairs and oil changes are only to be carried out in a service center.

Which malfunctions are not repairable

If we are talking about filter cleaning or routine maintenance, it is not a difficult task for any user. But in the case of serious problems where parts need to be replaced or checked on special test rigs, repairs by your own hands are inappropriate and even dangerous!

The service center will have to be contacted if necessary:

  • Compressor replacement;
  • Refrigerant leakage repair or charging;
  • Repair or replacement of electronic modules;
  • Change of oil;
  • Vacuuming of the system.

Replacement of thermal insulation and other complex manipulations that cannot be done at home.

Now you know how to diagnose your air conditioner, fix many of the problems and prevent problems with your climate control unit. Repairing with your own hands is not only saving money, but also the satisfaction of learning new skills and knowledge.

Like this post? Please share to your friends: