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The air conditioner does not turn on - reasons. The air conditioning compressor does not turn on. The external air conditioner unit does not work. Dantex air conditioner does not turn on.

If you are the proud owner of an air conditioner, then this article will help you cope with the panic that grips you when you are faced with the fact that your device does not turn on, especially when you expect it at an outside temperature of +45°C.

This situation, although unpleasant, is not hopeless. There are some reasons why the air conditioner refuses to turn on.

Experts highlight some of them:

    There is no electrical power or the air conditioner is in off mode;

    The timer is set incorrectly;

    The remote control does not work;

    The power supply to the air conditioner was turned off by the circuit breaker;

    The room temperature exceeds the device readings, etc.

What to Avoid First!

No matter how unpleasant the situation is, it is important to remember one rule - do not completely break it! You will definitely want to knock on the air conditioner unit or pull the cords, unscrew something or press the start button. All these actions will not help in any way, but on the contrary, can lead to significant malfunctions.

Often, the problem of an air conditioner not starting can be solved in a simple and cost-effective way, without the intervention of specialists. Let's look at some of them.

What should you pay attention to first?

Before purchasing a device, you should learn more about air conditioners. For example, about the principle of its operation, design and possible difficulties in operation.

For example, here are some conditions, the observance of which will help to use such equipment for a long time and uninterruptedly:

    Selecting the type of air conditioner;

    Installation by a specialist;

    Compliance with the conditions of use, according to the technical data sheet;

    Scheduled servicing of climate control equipment.

What to do if the air conditioner does not turn on?

There are always exceptions to the rules.

Let's look at some situations in which the air conditioner does not turn on.

1.Lack of power supply.

You don't need to be a professional electrician to determine that the air conditioner is de-energized. There are a number of possible reasons for this:

    The air conditioner plug is disconnected from the socket - turn it back on;

    The circuit breaker is knocked out - turn it on;

    The power cable is broken - needs to be replaced;

    We change the batteries in the remote control - this is often simply forgotten;

    The problem is in the internal circuit board of the air conditioner itself - we call a technician.

2. Air conditioner protection has tripped by mistake

Each air conditioner has internal intelligent protection and a diagnostic system. Such protections save the “life” of the device or its “internal organs”.

How to recognize that your device is stuck with an error?

    The indicators on the indoor unit panel flash in a certain rhythm

    When you try to turn it on using the remote control, the device emits a characteristic sound signal or the indicators start blinking

    An error code is displayed on the unit panel, which a technical passport can help you decipher.

A little about codes.

The fault code can be different, it helps to more accurately determine the malfunction of the air conditioner or will indicate a specific breakdown of any component. For example, the pressure sensor in the refrigeration circuit has tripped, the compressor has overheated, or the current consumption has increased, etc.

Example codes:

3.The ambient temperature prevents it from turning on.

According to the instruction manual provided for your air conditioner model, you can read under what conditions it will operate. For example, if it’s frosty outside, your air conditioner won’t start the compressor to cool, because it’s already cold. It may also not start to warm up the room if there is high humidity outside at a temperature of about 0.

In this case, you may need, t.s. equip your air conditioner model with a “winter kit”. This kit will help the air conditioner do its job, even if it’s -25 outside.

4. Refrigerant has leaked.

This problem is already more serious than just changing the batteries in the remote control. But still, there are clues that help determine whether a refrigerant leak has occurred or not.

Perhaps while operating the air conditioner, you noticed that it began to cool the air worse or even stopped starting in this mode. This is the first sign that there is a problem with a lack of freon. If you continue to operate it in this mode, while simply increasing the cooling temperature, then there is a high probability that the compressor will overheat and fail.

Therefore, do not panic, but inspect the block for oil leaks. If found, then everything became clear, the refrigerant had leaked. Even if you do not find visible evidence of a leak, we advise you to call a specialist who will carry out all the necessary diagnostics.

As they say, it is better to prevent a problem than to solve it; it costs more. This way you don’t have to change the compressor, which is quite expensive.

A little about a faulty compressor.

Anything made in a factory can break down, and your air conditioning compressor is no exception. Sad but true. Its breakdown may also be the reason for the unit not turning on.

An ordinary multimeter will help you determine whether it is broken or not. If you understand what we are talking about, then a few recommendations will be useful to you. If not, you can skip and read the last paragraph)

Set the multimeter to measure resistance. Next, having disconnected the air conditioner from the network, we find the compressor, remove the terminals and measure the resistance between the terminals. Ideally, the resistance reading between the main and starting windings should be equal to the sum of the resistance of each of the windings and the third terminal. The multimeter value may have an error of +/- 2%, but if the deviation is greater or the device shows OL, then this means the compressor is broken and must be replaced.

5. Control board.

This problem occurs more often than usual. The easiest and least expensive thing is a blown varistor fuse. Most craftsmen do not undertake to repair such boards, but try to install a new one, which is of course easier, but more expensive. But you can contact a service center that will repair the board.

Of course, the above reasons are not all, there are others, but these are the most common. If your nerves and time are valuable to you, then it is best to apply for the warranty that comes with your air conditioner. And remember, prevention is always cheaper than cure! This applies to all types of devices, and especially to climate control equipment.

Symptoms: indicators do not light up, control buttons do not respond

This is one of the few problems that the owner of an air conditioner can easily fix on his own, even if he does not have special tools. If the indicators on the electronic display do not light up, then most likely the air conditioner is not receiving power at all. Naturally, absolutely fatal cases such as a power outage throughout the house or entrance are not considered here.

First, check the power cable: visually everything should be in order, the plug is intact and undamaged, the wire is not pinched or melted anywhere, the plug is not hot to the touch. If the problem is in the plug, then either replace it, or, if it is not removable, replace the entire power cable. If the power cable is pinched somewhere, then it is better, of course, not to risk it and replace it.

It is quite possible that there are some problems in the electrical wiring at the place where the air conditioner is connected: this is easy to install - plug the power cord of some other electrical appliance into the outlet, which you just checked in another outlet. You can try plugging the air conditioner into a different outlet if the cable can reach it or you have a suitable extension cord. If no devices in the outlet work, first look at the electrical distribution panel: if you have a separate circuit breaker for sockets in your apartment, then it could simply be “knocked out”, and all you need to do is turn on the switch; However, the question remains, why it was “knocked out”. In other cases, you are still better off calling an electrician. If other devices do not work in other sockets, most likely, the power supply circuit breaker for the sockets throughout the apartment has been knocked out - you again need to go to the panel. By the way, if, after turning on the air conditioner again, the machine “kicks out” again, then your affairs are bad: such symptoms indicate the presence of a short circuit in the electrical network of the device, and here you cannot do without a technician.

It is possible that your power supply voltage is outside the limits allowed for this model: usually it is from 200 to 240 volts. If you have a voltmeter, check the voltage in the outlet: if it is not OK or there is nothing to check, you will have to call an electrician.

Power surge

If power surges in your apartment are a common occurrence, then be prepared for the air conditioners to react to them. Some models have protection against voltage surges: after this, the device does not turn on for several minutes. But if even after 10 minutes the air conditioner did not work, then the accident did not pass without a trace for her:

  • fuse burned out;
  • due to a short circuit, the wiring could fail;
  • The electronic control board is broken: the electronics are especially sensitive to voltage drops.

In any case, in such a situation, you should contact a specialist, even if it is just a blown fuse: firstly, in modern air conditioners there may be several of them, and, most importantly, you should not get into a complex modern device without special training.

And another piece of good advice: if you constantly experience power surges, purchase a voltage stabilizer and connect the air conditioner and other sensitive household appliances to the power supply through it.

Electrical wiring fault

A common reason for the lack of voltage in air conditioners is that the contacts in the compressor motor diverge or short out: if upon visual inspection blackened and charred contacts are visible, then this is the reason. In principle, you can straighten and clean the contacts from oxidation yourself, but it’s better to call an electrician.

During operation, wires may fall out of their mounting sockets, burn out, rub against the body, or be damaged. First, carefully inspect potential problem areas: if a visual inspection fails to detect a defect, you will need to ring each wire individually with a tester. If this does not help, call the workshop.

Breakdown to the body

A torn bare wire, for example, a compressor contact, can get onto the metal case and cause a short circuit with all the ensuing consequences.

Compressor short circuit

If the plugs are knocked out when the compressor is turned on, the cause may be a short circuit due to cycling of the compressor, or short circuit of the starting capacitors. This problem cannot be solved without special tools and skills, so it is better to call a specialist.

The remote control doesn't work

Rarely does anyone turn on the air conditioner through the control panel of the indoor unit, so if you press a button on the remote control and the air conditioner does not turn on, the thought immediately creeps in that the air conditioner is broken.

But the problem may be in the remote control itself: to verify this, try turning on the air conditioner directly from the air conditioner control panel. Most often the reason is simple - the batteries are dead - replace them and try again. If it doesn’t help, most likely the remote control itself is faulty - you need to buy a new one.

Sleep timer set

Turning on the air conditioner may be blocked if you set the shutdown timer yourself: carefully study the lit indicators on the remote control or control panel, look at the instructions.

Compressor faulty

The compressor is the heart of the air conditioner, and when something in it does not work, the entire device does not turn on. There are many possible causes, from which we can single out: a short circuit in the electric motor, breakdown of the motor winding or capacitor to the housing, destruction of the bearings, mechanical cycling, broken output or reduced capacitor capacity (the capacitor is changed), excessive refrigerant charging, faulty thermal protection relay and others.

As you can see, a compressor can fail for many reasons, and only a qualified specialist with the necessary equipment can accurately install it.

It's too cold outside

The compressor will not turn on if it is already too cold outside. If you want the air conditioner to work even at low temperatures, install the so-called “winter package”.

Outdoor unit overheating

If it is too hot outside and the outdoor unit is exposed to direct sunlight for a long time, it may overheat, which can cause damage to important components of the air conditioner, such as the compressor. Another potential cause of overheating is a refrigerant leak.

Freon leak

When the system is low on refrigerant, cooling efficiency is noticeably reduced and can even prevent the air conditioner from turning on. A freon leak is also dangerous due to potential overheating and breakdown of the most expensive component - the compressor.

Control module failure

Symptoms: any: if the control unit fails, it is impossible to predict its behavior: for example, the air conditioner can randomly turn on and off, indicators flash feverishly and similar madness

Of course, only a qualified specialist can accurately determine that a faulty control unit is to blame. And an unprepared person should definitely not get into it: the consequences will be fatal, including possible breakdowns of other expensive air conditioner components. Usually the control module is changed or reflashed.

In hot or cold weather, an air conditioner in an apartment can save you. It’s difficult without him in the summer. Owners of a split system cannot always figure out why the air conditioner does not turn on. There can be a number of reasons for a breakdown.

Sometimes the air conditioner stops turning on

Possible reasons

When you buy an air conditioner or split system, it is better to find out how it works, what kind of compressor it has, how well it cools, what problems may occur and how to monitor the normal operation of home appliances. If the system does not cool, you need to be careful and remember the safety rules:

  1. You should not disassemble the air conditioner or split system yourself, as this may cause more serious damage.
  2. There is no need to knock on the device, hoping that it will work.
  3. Do not press the power button too hard or press it several times in a row if you see that the air conditioner has stopped turning on.

It happens that household appliances stop working because of some little thing, and not at all because of a breakdown of the compressor, and then everything is easy to fix. It is better to carefully study the instructions for the equipment. In it you will find a solution to your problem.

Problem with the remote control

The first reason why an air conditioner does not work is the carelessness of its owner.

  1. Check your remote control. It may be that the batteries are simply inserted incorrectly. Then change them so that they are in the correct position.
  2. There is a possibility that the batteries in the remote control are simply discharged or exhausted. Then they need to be replaced with new ones. It’s good if you have the same spare ones at home or your batteries can be charged.
  3. If you have checked and replaced the batteries, but the air conditioner still does not cool, there is a problem with the remote control board. Then you need a master who can replace it.

Sometimes buying a new remote control can be quite difficult. It may not be in the store, then you will have to order it from the store. You can purchase a universal remote control. This device is suitable for most air conditioner models.

No power supply

Sometimes the problem is a little more serious. The power supply may be poorly connected to the indoor or outdoor unit. The reason why the air conditioner is not cooling the room may be due to a power outage. The problem may be in the outlet: there is no power to it. Check this by inserting any other device into it. Or the system cord is not plugged into the outlet.

Board failure

Sometimes the control board of the indoor unit may break down. Then it is necessary to replace the board or repair the old one. It's quite easy to do. When repairing the board, the internal unit is not removed. Repairing or replacing it may take up to two hours.

Changing modes

When the autumn cold sets in, there is a desire to use the air conditioner as a heater. To begin normal operation in such a situation, the equipment needs a little more time. It takes time for the pressure to equalize, so you just need to wait longer.

Starting protection mode

The air conditioner may not work due to switch-on protection. It is present in some devices and is triggered when performed incorrectly.

For example, if the outside temperature is -15 degrees, and it operates at a minimum temperature of -5 degrees. Re-read the instructions and find information about this.

You can install the so-called winter kit. This will allow restrictions to be lifted. Then the system will blow in almost any weather.

Error or timer

When the air conditioner stops cooling, it may display an error code. You need to read in the instructions what this error means and how to remove it. But, if you can’t cope with it, you need to contact a specialist. You could simply have set the timer incorrectly. This problem can also be resolved by reading the instructions.

In a situation where the equipment was purchased several months ago, the warranty period continues. At this time, you can call a specialist to your home, and you can be sure that you won’t damage anything yourself. Repairs can be made by the company that installed the climate control equipment.

If the warranty has not expired, you can use the services of a specialist

Call the master

The reason for the failure of the split system is unclear: you have checked the previous points, but the air conditioner still does not turn on, then you should call a specialist. There may be several reasons why the equipment does not cool. The cause may be the compressor or another part. Basically, all problems are fixed at the place where the air conditioner is installed, i.e. in your apartment, office, house.

But there are situations when it is necessary to remove the entire system and take it to a service center. Only specialists do this.

Filter contamination

Very often, the filters of the indoor unit can become dirty and too much dust can get in there. Then the system will weakly supply cool air or will not work at all. But it's not that scary. You can deal with this simply by washing the filter. However, to get it, you will need the help of a specialist. He has the necessary equipment and special skills.

Freon deficiency

Freon leakage is the next problem that can occur with your air conditioner. There is a danger that the equipment will overheat, jam and will not cool the air as it should if the freon level drops below the permissible level. Professionals say that you need to refill additional freon every one and a half to two years so that you don’t have to change it all. Such a replacement is quite expensive.

Rules of care

To avoid problems, every user should know how to properly operate the device:

  • you need to carefully and regularly clean the filters of the indoor unit;
  • if you see that water is flowing out of the indoor unit in droplets, the copper pipes are covered with ice, the air conditioner is not cooling enough, then you need to stop its operation and call a technician;
  • it is necessary to carry out regular maintenance: specialists must check the pressure in the system, the condition of the filters, the amount of freon, and the operation of the equipment in all modes;
  • You cannot turn on the air conditioner at sub-zero temperatures unless there is a winter kit attached to it.

Indoor unit filters should be cleaned regularly

Conclusion

To avoid problems with turning on the air conditioner, it is better to check it in advance and carry out preparatory work, if necessary. You can do this twice a year, since regular checks of climate control equipment prevent breakdowns and help cope with current ones.

Air conditioning systems are used very widely at the domestic level. And every year the number of home appliances that guarantee comfort only increases. In general, household air conditioners work properly and really help create more comfortable conditions. But during operation, air conditioner malfunctions remind you from time to time that this equipment is not completely perfect.

To be fair, it’s worth noting: the lion’s share of defects in household air conditioners are simple faults that can be easily fixed with your own hands. Let's consider the most common of them with reference to technological symptoms.

No cool air flow

The situation when a window (or other) air conditioner is turned on, but does not produce cold air flows, is often associated with a defect in the fan or fan motor.

The rotation of the fan blades creates an air flow passing through the cold tubes of the air conditioner evaporator.

Therefore, the absence of a flow of cold air at the outlet is a symptom that primarily indicates a fan malfunction.

Malfunctions of the fans of the internal units of air conditioners can cause the supply of cooled air in sufficient quantities to create the required comfort

Fan blades may spin slower than necessary or may not spin at all for various reasons. A side defect associated with the lack of cold flow can also be “overgrown” with an ice crust and for this reason unable to pass air. To determine an obvious fault:

  1. Remove the air conditioner housing.
  2. Check the impeller and fan motor.
  3. Check the fan blades for possible damage.
  4. Make sure the impeller is not blocked by a foreign object.

You should manually rotate the fan wheel to check for freedom and ease of rotation. If the motor shaft with the impeller mounted on it does not rotate or rotates with difficulty, the motor rotor may be jammed due to burnt-out stator windings. The burnt out engine will have to be replaced.


Replacing a fan motor on an indoor air conditioner unit is a fairly rare occurrence. Nevertheless, such moments happen in everyday life and require contacting service.

If the fan motor and impeller show working condition after diagnosis, most likely there is another problem - a more complex one. In this case, multivariate testing is required to identify the fault. Such tests should only be performed by qualified personnel.

Fan motor (compressor) capacitor

A window, split system, floor air conditioner can operate in cooling mode, but at the same time not supply cold air due to a problem with the capacitor of the fan motor (compressor).

The starting capacitor is designed for the initial start of installed motors. A capacitor malfunction may be accompanied by a slowdown in the fan motor rotor speed or complete blocking of the compressor motor.

If the compressor motor is noisy or the fan wheel turns very slowly, the start capacitor most likely needs to be replaced. This part is located under the air conditioner housing. Therefore you will have to:

  1. Remove the device body.
  2. Check that the impeller rotates easily.
  3. Inspect the power wires for damage.
  4. Inspect the capacitor for damage.

Visual inspection of the part, of course, does not provide complete confidence. Often, external signs of the integrity of the starting tank do not provide a reason for replacement. Therefore, it is advisable to check the capacitor with a pointer tester.


Checking the integrity of the capacitor using a measuring device. In this way, the malfunction and the need to replace this part, which can block the fan motor, is determined with high accuracy.

To do this, you need to disconnect the container from the air conditioner circuit circuit. Next, set the device to the resistance measurement mode in the “mOhm” range and touch the capacitor terminals with the probes of the device.

Swap the probes and perform the same operation again. If the needle on the tester scale deviates sharply and returns to zero, the capacitor is intact. Otherwise (zero reading or short circuit) replacement is required.

A common sign of a malfunctioning compressor starting capacitor is when the air conditioner starts to rotate quickly when starting, and then stops.

Electronic control panel or filter

The air conditioner may turn on, but not blow out cooled air, if there is a fault on the control board. For example, failure of the relay responsible for switching the power supply to the fan motor.

The control panel relays can also be tested for functionality using a multimeter. However, it is necessary to accurately determine the identity of the relay. Here you already need a schematic diagram of the electronic control board, and it is advisable for the master to be qualified as an electronics engineer.


Air conditioning fan relay on the electronic control board. Nearby there are two more relays of a slightly different shape that control other modules of the air conditioning system

If the air conditioning system is on but is not blowing cool air, it is possible that the air filter is completely clogged.

This air purification element, if not maintained, can accumulate a lot of dust over time, which will limit the operation of other functional units. As a result, the normal circulation of cold air is disrupted.

The air filter is usually located in front of the evaporator, just behind the front panel of the indoor unit. Removing and cleaning the air filter is simple (air conditioner instructions).

By the way, this work is a standard maintenance item on the user's part. At the same time, you should clean the evaporator grille if you notice an accumulation of dust and dirt. Warm water, soap and a soft brush are a classic cleaning kit.

Outdoor unit condenser

A common problem when there is no cold air supply is the condenser of the outdoor unit of the air conditioner (outdoor module).

This problem seems to be especially relevant for equipment installed in houses around which there are massive poplar plantations. Periods of poplar fluff leading to a complete blockage of air conditioner condensers.


Air conditioner condenser clogged with lint. This fabric is like a cotton blanket, completely covers the surface of the condenser and closes the passage to air flows

If the device turns on, works, but does not cool, there is every reason to inspect the outdoor module and clean it. Cleaning the condenser should be done with a soft nylon brush. If possible, use a vacuum cleaner with an attachment to clean baseboards. The use of water is not recommended.

Cooling and heating temperature control

If your air conditioner fails to produce cool air, it may be related to the temperature controller or thermostat. These circuit elements control the air temperature in the room and ensure that the compressor starts when necessary.

The cooling temperature controller is often equipped with a touch sensor, which is placed directly on the evaporator shell. There is also a protective thermostat, which is built into the contact block of the compressor.

Both thermostats are set to a specific temperature limit and turn off the compressor functions when the norm is reached or in the event of an emergency.


Air conditioner thermostat sensor, which is installed directly on the evaporator. Sometimes this sensor loses its ability to accurately measure temperature due to vibration.

If the temperature control or thermostat does not work properly, the compressor will not work. Accordingly, there is no cold air. That's why:

  1. The touch sensor should be checked for damage or broken wires and replaced if faulty.
  2. Check the thermostat at the lowest and highest temperature limits by testing its contacts with a multimeter.

The absence of readings from the measuring device indicates a malfunction of the thermostat. This device is usually beyond repair. It needs to be changed.

Lack of refrigerant in the system

The indoor and outdoor unit air conditioner fans rotate at normal speed. The operating mode settings correspond to the cooling functions, but the exhaust air is not cooled.

If all of the above actions do not bring the desired result, most likely there is a malfunction due to insufficient or complete absence of refrigerant.


Refilling the air conditioner with freon is possible with your own hands if you have the skills to handle equipment operating under pressure, as well as the appropriate accessories for refilling

Almost all household air conditioners are filled with R410A refrigerant. The amount of refrigerant charge in liquid form may vary depending on the model, but usually does not exceed 1 kg.

The exact amount of refrigerant to be charged can be found on the label of the outdoor unit or in the documentation of the air conditioner. However, to refill the air conditioner yourself, you will need some specific accessories.

  • manometric module,
  • high pressure hoses,
  • adapter fitting,
  • cylinder with freon R410A.

Therefore, refilling and filling with refrigerant is usually carried out by a professional service, despite the fact that do-it-yourself refilling saves three times money.

The absence of freon can be determined by some classic signs by following a simple diagnostic process:

  1. When you turn on the air conditioner, monitor what happens.
  2. Carefully inspect the union connections of the freon supply and suction tubes.
  3. When the air conditioner is operating, check the air temperature at the outlet of the condenser cooling fan.

If, when you turn on the air conditioner, the compressor turns on (can be determined by the change in sound) and, after working for 1-2 minutes, turns off, this is an indirect sign of the absence of refrigerant.


The air conditioning compressor of a traditional split system is usually located on the right side. This is what the entire structure of the outdoor unit looks like when the protective panels are removed from it

Also a sign of a freon leak is an oil film on the threaded fittings or on the tubes where they enter the fitting.

If such oil spots are detected and the compressor turns on in short cycles, these are signs that through the union connections.

The reason may be a loose tightening or, on the contrary, overtightening, when the copper tube simply bursts at the pressure point.

Universal air conditioner does not heat up

Modern models of air conditioning systems not only cool the air, but no less successfully heat it when the system is switched to heating mode. Heating is provided through reverse cycle technology.

Meanwhile, in practice, instability of the operation of such universal devices in each mode has been noted. The normal fault is normal in cooling mode and abnormal in heating mode. Or vice versa.


Resetting excess freon sometimes helps restore the functionality of a universal air conditioner in heating mode. But first it is advisable to measure the pressure in the system

Noticed: a common cause of malfunction, when there is cooling but no heating, is unbalanced refrigerant charging.

Typically, service technicians charge the air conditioner with an eye on the cold parameters, while ignoring the heating parameters.

However, if in the cooling mode the system is quite capable of operating even taking into account a slight deviation from the filling norm, then for the heating mode such a deviation is already critical.

Therefore, we can fully explain the result of troubleshooting, when by simply dumping the overfilled freon it was possible to start the air conditioner in heating mode. And after such a simple manipulation, the device worked properly in both modes for more than one year.

Practice of repairing household air conditioners

The video below demonstrates examples from the practice of diagnosing and repairing household air conditioners. A kind of visual aid for a mechanic will help you get more information on air conditioning systems:

There may be several situations when the outdoor (street) or indoor (in the room) air conditioner unit does not turn on. The simplest case is that the batteries in the remote control are low and the problem is solved by replacing them. Sometimes a regular reboot helps to get your equipment working again. To do this, just turn off the power on the air conditioner unit, unplug the cord from the outlet and return everything to its original state after a couple of minutes. Another standard situation is that the filters are clogged. It is recommended to wash them once every 3 weeks. You can do the cleaning yourself or invite a specialist.

Technical problems with the air conditioner

There are also more serious reasons why equipment does not work. The self-diagnosis system of modern Samsung and LG air conditioners is designed in such a way that if any problems are detected, the operation of the entire unit completely stops. A malfunction is indicated by flashing LEDs on the panel of the indoor (and sometimes outdoor) unit. The lights begin to light or flash in a certain sequence, which indicates a specific error. You can find out the reason why the Samsung aq09 and similar air conditioners turn off if you run the test mode. It is activated simply: just press the on/off button and hold for 5 seconds.

There are several reasons why the outdoor or external unit does not start. The most common are the following:

  • indoor unit temperature sensor error;
  • indoor unit fan motor speed error (less than 450 rpm);
  • indoor unit heat exchanger temperature sensor error;
  • option data error.

Error codes and solutions

Each of the listed system problems has its own code, which is displayed on the display. If several errors are detected, the one with the highest priority will be displayed first.

A malfunction of the room temperature sensor is indicated by error code 21. In order to fix the problem in the unit, it is necessary to disconnect the corresponding sensor (indicated as CN43 in the diagram) and measure the resistance. At an air temperature of 25 degrees it should be no more than 10 kOhm (an error of 3% is allowed). If the difference is significant, the sensor needs to be replaced.

The air conditioner's fan may also be faulty. In this case, error 54 will appear on the Samsung display. The problem can be solved in several steps. You must unplug the power cord from the outlet and return it to its place after 5 seconds. If power is supplied to the air conditioner unit and the Operation lamp is flashing, you should check the status of the semiconductor relay (labeled SS71). If there is no voltage and the relay does not start, then the reason for the non-working air conditioner is a processor malfunction, which entails changing the board.

The appearance of an error such as “the board is not programmed” requires its reprogramming. To do this, you need to have a remote control and a code table on hand. It is advisable to carry out this work at an authorized service center.