The situation when, instead of pleasant coolness, you hear an irritating crackling sound, but the air in the room remains warm, is familiar to many owners of climate control equipment. The air conditioner is crackling and not cooling - this is a classic symptom of a serious malfunction, which, if ignored, can lead to complete failure of expensive equipment. Users often mistakenly believe that simply turning the device off and on again is enough, but mechanical noise rarely goes away on its own.
The noise may come from the indoor unit where the evaporator and fan are located, or from an outdoor unit installed outside. The nature of the sound is critical: the dry crackling of plastic is different from the metallic clang of a compressor or the hum of bearings. Split systems various brands, whether budget LG or bonus Daikin, have a similar design, so the causes of breakdowns are often universal. Understanding the source of the sound is the first step to a successful repair.
In this article we will analyze in detail all the possible causes of crackling and lack of cold. You will learn how to carry out initial diagnostics on your own and in which cases calling a specialist becomes an absolute necessity. Do not delay in solving the problem, since the operation of a faulty unit can lead to a short circuit or destruction of key components of the system.
Mechanical damage to the fan in the indoor unit
One of the most common causes of rattling noise is a problem with the impeller. fan indoor unit. Over time, plastic blades can become deformed due to overheating or mechanical stress due to careless cleaning. When such a fan rotates at high speeds, it touches the walls of the case or other structural elements, producing a characteristic rhythmic crackling sound. In this case, the system may continue to blow, but air circulation is impaired, reducing cooling efficiency.
Another option is unbalance of the motor shaft or wear of the plain bearings. If the shaft has play, vibration occurs during rotation, which is transmitted to the plastic housing and amplified by resonance. Constant vibration can loosen the fastenings of the heat exchanger, which will lead to its depressurization and leakage of freon. Owners often notice that the crackling noise intensifies when switching speed modes.
⚠️ Warning: Attempting to lubricate the fan bearings with oil on the fly without disassembling the housing may result in grease getting on the electronics and causing a short circuit. Complete disassembly of the module is required.
To eliminate this malfunction, replace the impeller or the entire motor block assembly. Sometimes careful balancing helps, but in dusty environments this is a temporary measure. It is also important to check whether a foreign object has entered the air duct.
Drainage problems and icing
If your air conditioner is crackling but not cooling, water is often the culprit. If the drain tube is clogged or the drain slope is not correct, condensate begins to accumulate in the pan. At low evaporator temperatures, this water freezes, forming ice deposits. When the fan turns on, the blades may hit these ice blocks, making a loud cracking sound. In this mode heat exchange is broken and the cold does not enter the room.
Ice can form not only in the pan, but also directly on the evaporator tubes. This occurs when there is a lack of refrigerant or dirty filters. As ice expands, it deforms the plastic elements of the body and creates stress in the structure, which manifests itself in the form of a cracking sound during thermal expansion of the materials. Defrosting the system in this case is a mandatory procedure before further diagnostics.
- 🧊 Clogging the drainage channel with dust and dirt leads to reverse flow of water.
- 🌡️ Lack of freon causes a drop in pressure and temperature, causing icing.
- 🌀 Clogged air filters disrupt heat exchange, which also leads to ice formation.
To prevent the situation from recurring, it is necessary to regularly clean the filters and check the drainage patency. If ice has already formed, allow the system to completely defrost in fan mode before turning the cooling back on.
To check the drainage, pour a little water into the bath of the indoor unit (after removing the housing). If the water does not drain by gravity, the pipe is clogged or kinked.
Compressor malfunctions in the external unit
When a crackling sound comes from the street, and the indoor unit simply circulates warm air, the problem lies in compressor. This is the “heart” of the air conditioner, and its malfunctions are the most critical. A cracking or clanging sound in a compressor often indicates mechanical failure of internal components such as valves, pistons or bearings. The operation of such a unit is impossible, and an attempt to start it may lead to burnout of the motor windings.
Another cause of noise is water hammer. If liquid freon instead of gaseous freon enters the circulation system (which happens with improper filling or severe hypothermia), the compressor makes a sharp impact sound. Inverter models are more sensitive to the quality of installation and filling, so installation errors often appear this way. The vibration of a faulty compressor is transmitted to the metal tubes and body of the external unit, increasing the noise.
| Sound type | Probable Cause | Consequences | Difficulty of repair |
|---|---|---|---|
| Metal clang | Valve destruction | Complete loss of cold | High (replacement) |
| Loud knock | Bearing wear | Vibration, overheating | Medium (replacement) |
| Sharp click | Water hammer | Piston deformation | High (replacement) |
| Intermittent crackling sound | Start relay problems | Startup failure | Low (relay replacement) |
Compressor diagnostics require special tools such as a pressure gauge station and a tester. It is difficult to independently determine the exact cause without opening the circuit, but the nature of the sound often provides 80% of the information about the condition of the node.
Shell deformation and thermal expansion
Sometimes the cracking sound is not associated with the breakdown of mechanisms, but is a consequence of the physical processes of expansion and contraction of materials. The plastic from which the body of the indoor unit is made can produce sounds similar to cracking during sudden temperature changes. This is especially true for cheap models or older devices where the plastic has lost its elasticity. However, if the air conditioner stops cooling, the reason lies deeper.
Thermal expansion also affects the copper freon pipes. If errors were made during installation and the tubes are rigidly fixed or have tension, during heating and cooling they can rub against the walls of the housing or against each other, making sounds. In rare cases, this leads to microcracks and refrigerant leakage. Checking the fasteners and making sure there are gaps to accommodate expansion is an important part of maintenance.
Why does plastic crack more at night?
At night, the temperature difference between the operating air conditioner and the cooling room is maximum, which enhances the effect of thermal compression of materials.
It is also worth checking whether the screws securing the front panel are loose. The vibration of a running fan can cause loose plastic to rattle. Tightening the fasteners often eliminates extraneous noise without the need for complex repairs.
Foreign objects entering the system
Human factors and the environment often cause breakdowns. Rodents, birds or large insects may enter the outdoor unit, especially if it is installed on an open balcony or the ground without protective nets. Branches, nuts, or construction debris caught inside the fan can become stuck in the fan, causing a rattling noise and blocking rotation. As a result circulation the air stops and heat is not removed.
In the indoor unit, foreign objects are less common, but possible. These could be toy parts, buttons, or pieces of plastic that accidentally fell through the air intake grille. When operating at high speeds, such objects are thrown by centrifugal force towards the edges of the impeller, causing a lot of noise. A visual inspection through the grille will often reveal the problem.
- 🐦 Bird nests in the heat exchanger of the external unit block the airflow.
- 🍂 Foliage and poplar fluff are compressed and interfere with the operation of the blades.
- 🔩 Bolts or nuts forgotten by installers can rattle inside the housing.
Removing foreign bodies will usually solve the noise problem, but it is important to check that they have not damaged the fan blades or thin radiator fins. If the geometry of the blades is damaged, the unit will need to be replaced.
☑️ Diagnosis of foreign objects
Electrical faults and inrush currents
The cracking noise may be electrical in nature. For example, crackling of relay contacts or starting capacitor. If the capacitor is swollen or has lost capacity, the compressor or fan may not start normally, making a humming or cracking noise when it tries to start. At this point, no cooling occurs because the compressor does not gain speed. Electrical diagram The air conditioner is overloaded, which is a fire hazard.
It is also worth paying attention to the quality of the wire connection. Poor contact in a terminal block can cause sparking, which can be heard as a crackling noise. This is accompanied by a burning or melted insulation smell. In such cases, operation of the device is strictly prohibited until the malfunction is eliminated. Modern electronics split systems sensitive to voltage surges, which can also cause malfunctions in the control relays.
⚠️ Attention: If you hear an electrical crackle and smell burning plastic, immediately turn off the power to the air conditioner through the machine in the panel, and not through the remote control!
To diagnose the electrical part, you need a multimeter. The input voltage, the integrity of the motor windings and the capacitance of the capacitors are checked. Replacing a burnt capacitor is one of the most common and inexpensive repair procedures.
The influence of installation quality on system operation
Errors made during installation may appear months or years later. Improperly flared copper tubes eventually develop microcracks through which freon escapes. The system begins to work to the limit, trying to compensate for the lack of refrigerant, which causes overheating and noise. The vibration of a poorly secured external unit is transmitted to communications and indoors, creating a resonating hum.
It is also important to consider the length of the route. If the pipeline is too long or has many bends, it is difficult for the compressor to pump oil and freon, which leads to oil starvation and noise. Failure to evacuate the route during installation leads to moisture and air entering the circuit, which causes chemical reactions, corrosion and a characteristic crackling sound during operation.
High-quality installation in compliance with all technological standards prevents 90% of problems with noise and loss of productivity in the first 3-5 years of operation.
If you suspect installation errors, you will need to call specialists to audit the system, check the pressure and, possibly, refill in compliance with all technologies.
Frequently asked questions (FAQ)
Can I continue to use my air conditioner if it is cracking?
Strongly not recommended. A cracking sound indicates mechanical failure or electrical failure. Further work will lead to complete breakdown of the compressor or fire.
Why did the air conditioner stop cooling after winter?
During downtime, a blockage could form in the drainage tube, or insects could get in there. It is also possible that the oil in the compressor may freeze out or freon leak due to temperature changes.
How much does it cost to repair if the compressor burns out?
Replacing a compressor is an expensive procedure, often accounting for 60-80% of the cost of a new air conditioner. It is often more economically feasible to buy a new device, especially if the model is more than 7-10 years old.
How often should you clean your air conditioner to avoid cracking?
Indoor unit filters must be washed every 2 weeks during active use. It is recommended to carry out deep cleaning with disassembly and steam once a year, before the start of the season.
Will lubricating the fan help if it is cracking?
Temporary measure. If the bearing is already worn out and there is play, the lubricant will only muffle the sound for a short time. Soon the crackling will return with renewed vigor, and the motor will have to be replaced.