Why does a split system cool poorly: a review of common breakdowns and methods for fixing them

To ensure indoor climate control, modern sleeping systems are increasingly being used.They help achieve the most optimal air conditions not only in summer, but also in winter.

But already in the second year of using such equipment, its productivity decreases significantly. But why does the split system cool poorly? We have discussed all possible causes of this problem in this material. They also provided recommendations on how to fix simple breakdowns on your own.

Operating principle of the equipment

A split system is a climate control system for household or industrial use, consisting of two blocks: internal and outdoor. Each block has its own purpose and consists of different elements.

Interior contains in its housing an air filter, a powerful fan and a coil that allows you to cool the air. External part consists of a compressor, a capillary tube, a fan and a coil capacitor.

The split system is attractive for owners of large and small premises. It doesn't take up much useful space. And the modern design of the equipment allows you to complement the interior of any room

All split systems have the following classification:

• Wall mounted — their power is up to 8 kW;
• Floor-ceiling — their power is up to 13 kW;
• Cassette — their power is up to 14 kW;
• Channel and column — their power is up to 18 kW.

Less commonly used central And roof top (roof) installations.

The air conditioning compressor contains freon, a working fluid used to cool the air. It is fed through thin copper tubes. In the indoor unit, this liquid cools the air supplied from inside or outside the room.

If the split system is switched to heating mode, then freon will evaporate in the outdoor unit, and air conditioning will be done in the indoor unit.

Basic elements of split systems

Fan designed to increase the rate of heat transfer. The use of this part in the internal and external units allows you to significantly reduce the dimensions of the device.

Therefore, a significant part of the electricity consumption lies with these elements. Each manufacturer of climate control equipment is working to reduce the heating level of fans during rotation, reduce their size and noise level.

Compressor designed to drive the refrigerant. Freon in gas state is supplied to the condenser. Since this gas has low pressure, the compressor compresses it. This causes the temperature of the gas to increase. The substance entering the external unit quickly gives off heat and acquires a new physical state - liquid.

In this state, it enters the evaporator in the indoor unit. Freon evaporates, which reduces the air temperature in the room. Next, in gaseous form, the refrigerant again enters the compressor to complete the next cycle of operation.

From this we can conclude that the compressor is the most loaded element of split systems of all types.

The largest area in the external unit is occupied by the fan. But the compressor does most of the work. After the expiration of the equipment warranty period, it is necessary to closely monitor the performance of this element

Heat exchanger Both blocks have split systems. It is designed to speed up the heat transfer process. Without it, the transition of the refrigerant from liquid to gaseous state and vice versa would be too long.

The larger this element, the more efficient the heat transfer. To save useful space inside the case, manufacturers resort to the following solutions:

• lay the tube in a “snake” pattern;
• develop their own chemical compositions of copper alloys, which allow increasing the rate of temperature transfer;
• use additional gaskets in the gaps between the heat exchange tubes.

Since air from outside and indoors passes through the heat exchangers, it can clog the tube over time. This also happens if the air filter has not been changed for a long time.

A freon line is needed to move refrigerant in a split system. It is made of copper. In this climate control system, two types of freon pipes are used:

• copper pipe for refrigerant gas;
• copper tube for liquid freon.

The diameter of the first tube is slightly larger than the second.

We discussed in more detail the design and operating principle of the split system in this article.

The most common breakdowns

Failure of any of the listed elements will affect the efficiency of air cooling in the room.To understand what exactly caused the malfunction, it is necessary to consider the most common problems.

You should also consider ways to eliminate them in order to prevent the final failure of the equipment.

Failure #1 - power supply problems

It often happens that the voltage in the network is too low. It may be enough, for example, to turn on the fans. The sound of their operation will be heard by the user, but cooling will not occur, since the compressor will not be turned on.

220 V is the most optimal voltage for operating a split system. Up and down this value can vary by 20-30 V. Too significant a drop or increase in voltage can be detrimental to such equipment

To find out if this is true, you need to check the AC voltage in the network. If it is significantly lower than the required 220 Volts, then you need to turn off the equipment and wait for the power supply to normalize.

If the supply voltage regularly sags, for example, when someone turns on power equipment, then it is recommended to install additional devices: mains voltage converters and stabilizers. This will provide the climate control equipment with adequate power supply.

Failure #2 - lack of freon in the system

This problem occurs more often than others. The refrigerant evaporates from the system over time. Even if the equipment is not turned on for a long time, the gas will still slowly evaporate.

To make sure that the reason for the heat transfer failure lies in a small amount of refrigerant, it is advisable to contact a specialist. They have tools for checking the amount of freon in HVAC equipment.

According to the documentation that comes with the split system, its supply should be replenished at least once every two years for those who use the device at home.

What you need to know before replacing the refrigerant:

• Freon comes in different brands, the required brand is indicated in the documentation for the equipment;
• access to the outdoor unit is required for refueling;
• Before replacing, you need to check the freon level in the system.

If the equipment is used in production or in conditions of a significant temperature difference between the street and the room, then replacement is carried out once a year. By the way, charge the system with freon You can do it yourself.

Replacing freon is a very responsible process. To implement it, you need the refrigerant itself, a container for it, electricity and control devices. They serve to measure the volume of gas in the system

Among the reasons that may cause a lack of substance in the system, it is worth highlighting:

• manufacturing defects, for example, refrigerant was underfilled due to an automation failure;
• damage to the freon pipe during installation or transportation;
• increasing the size of the route without refilling freon.

In the first case, a malfunction can occur even in equipment that has just been purchased. A lack of freon will not allow you to quickly cool the room. This occurs due to excessive heating of the compressor.

The problem will be solved by replacing the equipment with a serviceable one or warranty service, refueling.

In the second case, self-refueling will not work. This is due to the fact that the refrigerant will still leave the system through damage in the copper pipe.

Before refueling, it is necessary to find the location of the breakdown and solder it if the conductor itself is damaged. We recommend that you read soldering instructions copper tubes.

In the third case, you also need to refill the equipment with cooling gas.

This is what the taps used to refill freon into the split system look like. Due to the fact that refrigerant refilling is carried out on the external unit, all work must be carried out with special care. If access from the premises to the unit is difficult, then it is necessary to use a tower

It is worth considering that a long-term absence of freon in the required quantity significantly reduces the service life of the compressor. Repairing or replacing it will take more money and time. Therefore, it is recommended to carry out regular inspections of split systems by specialized specialists.

Failure #3 - fan malfunction

As a rule, this malfunction occurs in split systems that have been used for more than 2-3 years. This is also possible when equipment operates in conditions with very polluted air.

There may be several reasons for the breakdown:

• jamming of the fan bearing due to lack of lubrication and clogging;
• damage or deformation of the blades;
• a malfunction in the operation of the control board, for example, liquid has entered or one of the piping elements has failed;
• failure of the fan motor - jamming, short circuit or power failure.

Another option is also often encountered: the fan is working, but the air flow is blocked by a layer of dust. Due to these reasons, cooling efficiency decreases.

The most important part of a split system fan is the motor. If it fails, the fan stops working. A stable voltage is required to power this motor.

Unfortunately, it is difficult to fix this problem yourself, short of cleaning the grille.Diagnosing the problem will require a variety of tools and skills.

It often happens that a breakdown can be fixed fairly quickly. For example, replace wires or restore connectors. If the fan motor fails, it is replaced with a new one. This will maximize the service life of the equipment.

If the control board is faulty, then the damaged elements can be dismantled and replaced with new ones. If the damage is extensive, it is easier to replace the entire board.

Failure #4 - valve failure

This part is needed to switch between heating and cooling modes. If it fails, warm air will be supplied to the room in two operating modes.

This malfunction is infrequent, but it can also be the reason that warm air comes from the split system.

This is what a four-way valve looks like in cross-section. This is a technically complex device, repair of which is possible in rare cases. It makes it possible to change the direction of freon circulation, which allows you to use a split system for heating

To eliminate it, you will also need qualified help. This is due to the fact that it is not easy to identify: the panel will show the full operation of the device in two modes.

The breakdown is solved by replacing the four-position valve. Some craftsmen completely remove this part from the structure. In this case, the cooling function will be restored, but it will not be possible to heat the air.

Failure #5 - capillary pipeline clogged

With this malfunction, there may be no cooling at all. Less often it is weak. This happens for the following reason: a partially clogged tube leads to an increase in the pressure difference at the inlet and outlet of the pipeline.

Due to the high pressure difference reading, the freon begins to boil before reaching the evaporator in the indoor unit. Therefore, most often there will be no cooling at all.

You can verify the breakdown by seeing the appearance of ice on the copper tube (before the evaporator). Another characteristic feature of this malfunction is the constant operation of the compressor with very rare stops or without them at all.

If the tube is completely clogged, the refrigerant circulation stops. In this case, the device will work constantly, but the air will be supplied warm.

Replacing capillary tubes is the most rational solution for restoring the functionality of the split system. To dismantle/install them you will need wrenches. It will also be necessary to restore the insulation layer

A competent specialist can fix this. Partial blockage can be removed by blowing air. This requires special equipment, since the air is supplied under pressure.

If the blockage is complete, resort to hydraulic cleaning. Various brands of solvents are also used. If there are multiple blockages and they cannot be eliminated using the methods listed above, then the tube must be desoldered and replaced with a new one. For more information on cleaning the system yourself, we brought here.

Failure #6 - compressor malfunction

If only the fans work when you turn on the electrical appliance, this indicates a possible breakdown of the compressor. In this case, the refrigerant does not circulate through the capillary tubes, and the air supplied to the room is at room temperature.

To solve this problem, it would be a good idea to familiarize yourself with self-help methods. compressor diagnostics.

Repairing and replacing the compressor will cost the most.The damage can only be repaired if this element is jammed. If the technician manages to wedge the jammed parts, then subsequent operation of the equipment is possible.

In other cases, it is replaced with a new one. Due to the fact that it most often fails after the end of the warranty period, it is most advisable to replace the external unit. This must be done because other parts in this block also have serious wear.

After repairing or replacing the split system compressor, you will need to replenish the refrigerant in the system. After the technician performs a test run of the equipment, the climate control equipment can be fully used

It is also worth paying attention to the fact that the compressor may not turn on for other reasons.

The main ones:

• faulty starting capacitor;
• malfunction of the working capacitor;
• Thermal relay malfunction.

The starting capacitor is used in the design of split systems to start the compressor when power is supplied to it. If it fails, then the engine will not be able to work. Replacing the capacitor will not take much time and money.

Running capacitor serves to maintain engine operation in a stable condition. This element can dry out, losing its capacity. If it becomes inoperative, the compressor may turn on, but then immediately stops working. Replacing the run capacitor is also not expensive.

A thermostat necessary to protect the engine from overheating. If it fails, then the power from the network does not reach the compressor and it cannot turn on. This part is also inexpensive to replace.

Failure #7 - sensor failure

Typically, sensors in a design rarely break down.But their malfunction can affect the performance of all equipment. If they break down, there will be cooling, but it will not be sufficient.

The device will be unstable and will not turn on for long. Error codes will appear on the split system display.

This is what the sensors look like. Each of them has its own temperature measurement limit. Manufacturers of split systems install such electronic components on a heat sink or place them in a separate housing made of heat-conducting material

In the equipment instructions, each code indicates the failure of a specific sensor.

There are three of them in the split system design:

• indoor unit thermistor — a sensor that controls the air temperature in the room;
• evaporator thermistor — controls the temperature at the outlet of the system;
• capacitor thermistor — controls the temperature at the entrance to the system.

A malfunction of any of them results in the control unit receiving unreliable signals. Because of this, commands are issued to the compressor to stop working, despite the fact that the desired room temperature has not been reached.

Failure #8 - malfunction of electronic boards

The indoor unit contains the control unit. The board contains electronic components and a microprocessor. If the cooling is insufficiently effective or absent altogether, the problem may lie in the failure of this board.

Several types of electronic components are soldered on the control board. Each of them performs its own functions. Damage to one of them can lead to disruption of the split system.

In some cases, for a complete repair you will only need a soldering iron and spare parts to replace damaged components.

Local faults can be corrected: failed relays, signal amplifiers, capacitors. If liquid has been spilled on the board, for example, or there is serious mechanical damage, then it is completely replaced.

A faulty board may cause the internal fan to lose power. Therefore, cold air will enter the room very slowly.

In inverter-type split systems there is another board. It is located near the compressor. Failure of this electronic unit may cause a loss of power supply to the motor. The method for repairing this board is similar to that described above.

Failure #9 - clogged air filters

There are air filters on the indoor and outdoor units. If one or two of them is clogged, the air flow is significantly reduced. Cooling efficiency is noticeably reduced. Water may drip from the split system, and ice may form on the copper pipes.

You can clean the filters yourself if you follow the instructions in the technical description of the split system. For regular filter maintenance, it is best to contact qualified technicians.

If this problem is not corrected for a long time, then the evaporator and fan become clogged. While the filters can be cleaned quickly enough, removing clogs from the evaporator and fan takes a lot of time and effort.

To do this, you will need to completely disassemble the indoor unit. Therefore, it is recommended to regularly monitor the condition of the filters in both units. Modern systems have coarse and fine air filters.

It is not recommended to repair equipment yourself. This requires special tools. You will also need additional parts to replace those that have failed.Also, do not forget that working with electrical appliances is life-threatening, since the mains current can kill a person.

Conclusions and useful video on the topic

This video describes an example of servicing the indoor unit of a modern split system:

Each breakdown has its own reason. In some cases, the malfunction can be eliminated by simply cleaning the filters or grille from dirt. Therefore, it is advisable for every owner to know how properly serviced split system.

But, in all other cases, skills in diagnosing and repairing such complex equipment as split systems are required. Our technicians will do the job as quickly as possible and guarantee the functionality of the device.

Would you like to supplement our publication with useful recommendations for diagnosing and repairing a split system? Or did you notice a discrepancy in the material presented? Please write your comments in the block below this article.

If you have problems with your split system and you can’t determine the cause of the problem, ask our experts for advice - we and other site visitors will try to help you.