Suddenly appearing extraneous noise from household appliances always causes concern for the owner. Especially if it cracklingoccurs when the unit starts or stops. Many users immediately begin to panic, assuming a critical engine breakdown or a freon leak that requires expensive intervention.
However, these sounds do not always indicate a malfunction. In some cases refrigerator it produces specific clicks and crackles due to the peculiarities of its design and thermodynamic processes. Understanding the physics of the compressor and refrigerant circulation system helps distinguish normal operation from a real problem.
In this article we will examine in detail the mechanical and electrical causes of noise. You will learn when you can sleep peacefully, and in what situations immediate diagnostics and replacement of units is required. It is important to correctly interpret the signals that your household appliance gives.
Physics of the process: thermal expansion of materials
The most common and absolutely safe cause of cracking is a change in the temperature of the internal elements of the case. When the compressor is turned on, active cooling of the evaporator and chamber walls begins. The plastic from which the inner box is made and the metal of the pipelines have different coefficients of thermal expansion.
When the temperature drops sharply, the materials compress at different rates, creating stress at the attachment points. It is this process that is accompanied by a characteristic crackling sound, reminiscent of the cooling of a TV with a CRT monitor that has just been turned off. Typically, such sounds do not last long until temperature gradient stabilizes.
⚠️ Attention: If the cracking sound is accompanied by the smell of burnt plastic or rubber, immediately unplug the device. This may indicate overheating of the wiring or melting of the insulation, which is a fire hazard.
The intensity of the sounds depends on the quality of the plastic and the thickness of the chamber walls. In budget models with a thin internal coating polystyrene it can react to temperature changes more loudly. Over time, after several cycles of freezing and defrosting, the material “gets used to it” and the noise may become quieter.
Why do old refrigerators crack less?
Old models often had a thicker metal inner box, which is less susceptible to deformation when temperature changes than modern ones plastic.
It is also worth considering the humidity in the chamber. Condensation, freezing on the walls or elements of the system No Frost, can create additional stress, which is released with a characteristic sound. This is a natural process that does not require the intervention of a specialist.
Operation of the starting relay and electrical circuit
The second most frequent source of sounds is the electrical part of the unit. The starting relay is responsible for starting the compressor engine. When voltage is applied to the motor windings, the contacts close, which is often accompanied by a loud click or a series of quick clicks.
If you hear a distinct metallic clang or crackling sound exactly the second the motor turns on, it is most likely the relay. Older models used posistor relays, which could produce louder sounds when activated. Modern devices are quieter, but they are not without acoustic effects.
- 🔊 A single loud click is the norm for most models at startup.
- 🔊 A series of frequent clicks before starting is a sign of an attempt to start (may indicate problems with starting).
- 🔊 Continuous crackling noise during operation - possible sparking in the circuit or a malfunction of the relay.
It is important to distinguish the nature of the sound. If it's a soft click, there's nothing to worry about. But if a dry, sharp crackling sound is heard, similar to an electric discharge, this is a reason to check contacts. Loose or oxidized connections can spark, creating interference and noise.
Frequent switching on and off of the relay (clocking) can also be caused by unstable voltage in the network. If your network experiences spikes, the trigger may not fire correctly, making repetitive sounds. In such cases, it is recommended to use a voltage stabilizer.
Vibration of the compressor and fastening elements
The compressor is the heart of the refrigerator, operating in pulse mode. When started, the piston group begins to move, creating vibration. If the motor mounts are loose or the damper pads are worn, vibration is transmitted to the housing and tubes, causing rattling and crackling.
Particular attention should be paid to the copper pipes of the cooling system. They are located in close proximity to each other and to the body. During startup, when refrigerant under pressure rushes into the system, the tubes may shift slightly and hit each other or the cabinet walls.
To eliminate this phenomenon, it is often enough to carefully straighten the tubes by hand (only when the refrigerator is turned off and defrosted!), increasing the gap between them. However, this must be done extremely carefully so as not to damage the thin metal and not provoke freon leakage.
| Type of sound | Probable cause | Danger | Actions |
|---|---|---|---|
| Deaf crackling sound at start | Thermal expansion of plastic | No | Observation |
| Metal clanging | Touching of tubes or relay | Low | Checking fastenings |
| Dry electrical crackling | Sparking contacts | High | Call masters |
| Gurgling and crackling | Freon movement | No | Normal |
If the compressor is mounted on rigid metal brackets without rubber shock absorbers, noise will be much stronger. In some budget models, manufacturers save on vibration isolation, which is a design feature and not a defect.
Problems with the No Frost system and fan
In refrigerators with a system No Frost the fan is responsible for circulating cold air. When you turn on the refrigerator, the fan starts simultaneously with the compressor or with a slight delay. If ice has formed on the blades or in the fan bearing, it will operate noisily.
Ice can get into the gap between the blades and the fan housing, causing a characteristic cracking or knocking sound. This often happens if the drain hole is clogged and the water does not drain, but freezes in the evaporator area. In such cases, complete defrosting of the unit is required.
⚠️ Attention: Do not try to forcefully turn the fan or clean off the ice with sharp objects. Damage to the blades will lead to imbalance and even more noise, and a breakdown of the evaporator housing is fatal for the refrigerator.
The fan bearing itself may also be the cause of the crackling sound. Over time, the lubricant in it dries out, and it begins to hum or crackle when the speed increases. Replacing the fan is a simple procedure, but requires disassembling the back panel of the freezer.
☑️ Fan diagnostics
Sometimes the fan blades can touch wiring or other elements if they were incorrectly laid during a previous repair. In this case, extraneous sound will occur cyclically, with the speed of rotation of the impeller.
Compressor malfunctions: when it’s time to sound the alarm
The most serious cause of crackling noise is internal problems of the compressor itself. If the piston group is worn out, the valves are damaged, or there are problems in the lubrication system, the engine will operate with increased noise levels. Such a crackling sound is often accompanied by strong vibration of the entire body.
A dangerous sign is a metallic knock, which intensifies as the engine warms up. This may indicate that the connecting rod and piston group has play. The operation of a refrigerator with such a defect is short-lived - the compressor can jam at any moment.
Another symptom is a buzzing crackling sound when trying to start, after which the compressor turns off. This indicates that the engine cannot turn over due to high pressure in the system or mechanical jamming. At this moment, the start relay clicks, trying to start the unit.
It can be difficult to diagnose the condition of the compressor “by ear”. Experienced craftsmen use a stethoscope or a long screwdriver with their ear to the handle to localize the source of the sound inside the motor housing. It is strictly forbidden to climb inside the compressor on your own.
Methods of self-diagnosis and elimination
Before calling a technician, you can carry out a number of simple manipulations that will help identify the cause of the noise. Often the problem is solved by simply defrosting or leveling the position of the refrigerator.
First, check the installation of the unit. If the legs are not adjusted and the refrigerator is not level, the misalignment causes additional stress in the frame and tubes. Use a building level to check. The case should not wobble when lightly pressing on the corners.
- 🛠️ Check the distance to the wall: the gap should be at least 5-10 cm for normal ventilation.
- 🛠️ Make sure that the refrigerator does not touch other pieces of furniture or walls.
- 🛠️ Inspect the rear grille: there should be no foreign objects (rags, bags) that can vibrate.
If you find that the tubes are touching at the back, carefully (after disconnecting!) separate them. You can also use special vibration-isolating pads under the legs if the floor in the room is uneven or resonates.
⚠️ Attention: Specifications and location of elements may vary depending on the model. Always check the manufacturer's official instructions before disassembling or mechanically impacting components.
Try to completely defrost the refrigerator within 24 hours. This will help remove ice plugs in the No Frost system and eliminate cracking noise caused by ice on the fan or evaporator. If the sound returns after defrosting, the problem is mechanical or electrical.
Frequently asked questions (FAQ)
Is it normal for the refrigerator to crack only at night?
Yes, this is quite normal. At night, the overall noise level in the apartment decreases, and you begin to hear sounds that were drowned out during the day. In addition, at night the compressor cycles more often, since the refrigerator is opened less often and the temperature regime is more stable.
Can a new refrigerator crack?
A new unit can make sounds of thermal expansion until the materials “grind in.” Also, when loading food for the first time, the compressor may work in increased mode, creating more noise. If the crackling is not accompanied by other symptoms, there is no need to worry.
Why does the crackling appear after defrosting?
After defrosting, moisture may remain in the system, which, when frozen, forms an ice crust on the moving parts (fan). Also, a sharp temperature difference when turned on for the first time after inactivity causes intense compression of materials.
Is cracking noise dangerous for food in the refrigerator?
Sound itself does not affect the safety of food. However, if the cracking noise is caused by a compressor malfunction or loss of seal, the temperature in the chamber may no longer be maintained at the desired level, resulting in food spoilage. Monitor the temperature.
How long can the refrigerator crack when you first turn it on?
Primary cooling can last up to 24 hours. During this period, sounds may be more intense. If the cracking does not go away after two days of operation or becomes louder, diagnostics is required.