An unexpected crash coming from the back of the refrigeration unit can scare any owner of household appliances. This sound often indicates physical processes occurring within the cooling system or mechanical problems with components. Understanding the nature of noise is the first step to preventing more serious failures that can lead to food spoilage.
In most cases, the characteristic sound is associated with the expansion or contraction of materials under the influence of temperature changes. However, you should not ignore regular and loud crackling noises, as this may indicate a malfunction compressor or malfunction of the evaporator. Next, we will analyze in detail the main factors influencing the acoustic comfort of your kitchen.
Physics of the process: thermal expansion of materials
The most common and absolutely natural cause of cracking is thermal deformation of plastic and metal. The internal chamber of the refrigerator and its rear wall undergo cyclic cooling and heating during the operation of the thermostat. The materials from which the internal panels are made have different coefficients of thermal expansion.
When compressor turns on, the temperature inside the chamber drops sharply. The plastic interior lining shrinks faster than the metal frame or insulation layer. It is at this moment that the layers shift relative to each other, which causes a characteristic click or crackle. This process is absolutely normal for most models, including the compressor. The intensity of the sounds directly depends on the temperature difference between the on and off state of the unit. If you set the mode Indesit, Atlant And Beko.
The intensity of the sounds directly depends on the temperature difference between the on and off state of the unit. If you have set the mode Super freezing, the temperature difference will be sharper, and accordingly, the crackling will become louder and more frequent. Over time, when the materials “grind” to each other, the noise level may decrease, but will not completely disappear.
Problems with compressor and start relay
The situation becomes more serious if the source of the sound is not just deformation of the plastic, but the engine itself. Compressor is the heart of the refrigerator, and any extraneous sounds in this area require attention. Often a cracking noise occurs when the motor is trying to start, which indicates problems with the start relay or windings.
If you hear a loud click, followed by a hum, and then another click and silence, this is a sign that the motor is unable to start. The start relay clicks, trying to give an impulse, but due to a voltage surge or wear on the mechanism, the start does not occur. Repeated cycles can lead to overheating and failure of an expensive unit.
It is also worth paying attention to the fastening of the compressor itself to the frame. Over time, shock absorbing pads can dry out or become dislodged. As a result, the vibration of the running motor is transmitted to the metal body and rear wall, causing rattling and periodic cracking. In such cases, it may be necessary to tighten the mounting bolts or replace the rubber washers.
⚠️ Attention: If the compressor operates continuously, gets very hot, and periodic loud clicks are heard from behind without switching to cooling mode, you must immediately disconnect the device from the network and call a specialist.
Deformation of the evaporator and No Frost system
In refrigerators with a system No Frost or Low Frost the back wall hides the evaporator. The circulation of cold air is provided by a fan, and defrosting occurs automatically. Cracking in this area is often associated with the process of thawing ice on the evaporator.
When it turns on Defrost heating element, the ice crust accumulated on the radiator begins to heat up sharply. The ice cracks, breaks off and falls onto the heating element, producing characteristic sounds similar to gunshots or a loud crack. This phenomenon is especially noticeable after the refrigerator has been operating for a long time without opening the door.
Another reason may be ice freezing on the fan blades. If the drainage system is clogged, the water does not drain and freezes in unintended places. The rotating fan brushes against frozen ice, causing an intermittent crackling or humming sound. In this case, it is necessary to defrost the unit and clean the drainage hole.
How to check the fan?
To check the fan in the No Frost system, it is often necessary to remove the back plastic panel inside the freezer. Before doing this, be sure to disconnect the refrigerator from the power supply for 10-15 minutes.
Mechanical damage and foreign objects
Do not discount trivial mechanical reasons. The back wall of the refrigerator is an area where dust, animal hair and small debris often accumulate. The entry of foreign objects into the area of a working compressor or fan can cause a rhythmic crackling sound.
It is also important to check whether gas pipes, furniture or other household appliances are touching the rear of the refrigerator. The vibration transmitted from the operating unit causes the contacting surfaces to resonate. It is enough to move the refrigerator a few centimeters to eliminate this effect.
In rare cases, a cracking noise may be caused by damage to the blades of the condenser fan located next to the compressor (in some models). If the blade is cracked or warped, it will hit the guard with each rotation. A visual inspection of the rear panel will help identify such defects.
☑️ Diagnosis of external causes of noise
The influence of incorrect installation and alignment
Correct installation of the refrigerator is the key to its quiet operation. If the unit is not level, the load on the compressor is distributed unevenly, which increases vibration. A skewed case leads to the fact that internal elements begin to touch where there should be no gap.
Be sure to check the adjustment supports on the front panel. They must be unscrewed so that the refrigerator is stable, but with a slight tilt back for the doors to close correctly. An unstable position causes the body to sway when the motor is running, which generates additional sounds.
In addition, the floor under the refrigerator must be flat and hard. If there is a soft rug under the unit or the linoleum has waves, the vibration will be poorly damped, causing hum and rattling of the entire structure. In some cases, special anti-vibration pads are placed under the supports.
Comparative table of causes of noise
For ease of diagnosis, we suggest that you familiarize yourself with the table systematizing the main causes of rattling noise and methods for eliminating them. This will help you quickly navigate the situation and understand whether you need to call a specialist.
| Sound type | Probable cause | Danger | Actions |
|---|---|---|---|
| Rare clicks when start/stop | Thermal expansion of plastic | Absent | Observation |
| Loud cracking + water on the floor | Drainage clogged / Ice on the fan | Medium | Defrosting, cleaning |
| Series of clicks, the motor does not start | Malfunction of the starting relay | High | Replacement relay |
| Constant metal clanging | Touching pipes or objects from behind | Low | Unit displacement |
Frequently asked questions and answers (FAQ)
Why does the refrigerator crack only at night?
At night, the overall noise level in the apartment decreases, and even the standard sounds of equipment operation become more noticeable. In addition, at night the refrigerator may work more intensely due to the lack of door opening and stable room temperature, which leads to rarer but longer compressor cycles.
Is it dangerous if a new refrigerator is cracking?
A new unit is characterized by a “breaking in” period. The plastic elements of the inner chamber have not yet gone through full cycles of expansion and contraction, so they may produce louder sounds. If the cracking sound is not accompanied by loss of cold, there is nothing to worry about.
Is it possible to lubricate the rubbing parts yourself?
Lubricating the internal plastic panels or the evaporator is strictly prohibited. This may cause the plastic to chemically degrade or lubricant to get onto the food. Only mechanical components, such as fan bearings, require lubrication, but it is better to entrust this procedure to a specialist.
How long can a refrigerator with a cracking relay operate?
Operating a refrigerator with a faulty start relay that makes frequent clicks is only possible for a short time. Operation in this mode leads to overheating of the compressor windings and eventual combustion. It is recommended to fix the malfunction within 1-2 days.
Does the temperature in the room affect the cracking?
Yes, it does directly. The higher the room temperature, the more often the compressor turns on and the greater the temperature difference inside the chamber. In hot weather, cycles of expansion and contraction of materials occur more often, increasing the number of sound effects.