A sound reminiscent of a loud bang or click coming from a working refrigerator can scare even an experienced user. Often, equipment owners wonder who exactly slams the door if no one is in the house, or whether this sound is a sign of a serious breakdown. In fact, in most cases, the source of the acoustic effect is the unit itself, or rather, its physical properties and the operation of internal systems.
Understanding the nature of these sounds is necessary in order to distinguish normal functioning thermal expansion from real malfunctions. Sudden changes in temperature inside the chambers and on structural elements cause deformation of materials, which gives rise to a characteristic crack or pop. However, sometimes behind this lies a more complex problem that requires the intervention of a specialist.
In this article we will analyze in detail all the possible causes of loud clicks, methods for diagnosing them and ways to eliminate them. You will learn how to distinguish the sound of breaking ice from problems with compressor, and whether you should worry if the refrigerator makes such sounds immediately after turning on.
Physics of the process: thermal expansion of materials
The most common reason for creating the illusion that someone slams the door or knocks on the body, it is a banal thermal expansion. The inner walls of the refrigerator compartment, the evaporator and other plastic elements contract during sudden cooling, and when heated, they expand. This process is accompanied by sound effects, which can be quite loud.
This phenomenon is especially often observed in refrigerators with a system No Frostwhere temperature changes are sharper and more frequent. The plastic from which the internal panels are made has a certain expansion coefficient, and when the operating mode of the unit changes, it can make sounds reminiscent of gunshots or pops. This is absolutely normal for new equipment or after defrosting.
If you notice that popping noises occur cyclically, approximately once every 10-15 minutes, then with a 99% probability your refrigerator is working. Thermal deformation is a natural physical process that does not require repair. Over time, when the materials “grind” to each other, the intensity of the sounds may decrease, but they may never disappear completely.
⚠️ Attention! If the claps are accompanied by vibration of the housing or movement of the unit from its place, it is necessary to check the stability of the installation. An uneven floor can increase resonance from thermal expansion.
Operation of the compressor and start relay
The second most common source of loud sounds is starting and stopping compressor. When the motor is turned on, the starting relay gives an impulse, which may be accompanied by a distinct click. If this click is very loud and sharp, it is easily perceived as a door slam.
Particular attention should be paid to the nature of the sound when the compressor is turned off. In older models or units with worn starting protection equipment, a so-called “soft start” may occur with a delay, which is sometimes accompanied by a shock. It is also worth checking the condition of the mounts of the motor itself: if the rubber shock absorbers are worn out, the vibration will be transmitted to the body, causing rattling and knocking.
Modern ones inverter compressors operate much quieter and do not make sharp startup sounds, since they do not stop completely, but only change power. Therefore, if your refrigerator is equipped with an inverter, but makes loud popping noises, the reason most likely lies not in the motor, but in other components.
- 🔊 A loud single click at startup is the norm for many models.
- 🔊 A series of fast clicks without starting the motor is a sign of a relay malfunction.
- 🔊 A dull knock at the end of the operating cycle is a possible problem with depreciation.
Why are inverter refrigerators quieter?
Inverter motors do not have a rigid start-stop cycle. They pick up speed smoothly and operate constantly at low speeds, maintaining the temperature. The absence of a sharp start eliminates the mechanical shock and loud acoustic click of the start relay, characteristic of classic compressors.
Defrost system and ice plugs
In units with an automatic defrost system, the heating element is periodically heated to melt the ice on the evaporator. When the ice crust that has accumulated over the operating cycle begins to heat up sharply, it can crack and break off in large pieces. The fall of such pieces of ice onto metal parts or the bottom of the chamber creates a sound very similar to a blow or pop.
In addition, an ice plug may form in the drainage system. When the defrost mode is turned on, the pressure in the tubes changes, and the plug may fly out or move with a bang, creating a sharp sound. This often happens if the drain hole is dirty or frozen.
If you hear such sounds, it is recommended that you conduct a visual inspection of the back wall of the refrigerator compartment. The presence of ice or icicles can confirm the hypothesis of problems with defrosting. In some cases, it is necessary to clean the drainage or replace The defrost heating element.
| Type of sound | Probable cause | Need for repair |
|---|---|---|
| Loud crackling | Thermal expansion | No |
| Sharp click | Start relay | Only in case of startup failures |
| Blow/Plop | Falling ice | Checking the defrost system |
| Metal clanging | Touching the compressor tubes | Yes, adjustments are required |
Problems with the fan in the system No Frost
Refrigerators operating using technology No Frostare equipped with fans for air circulation. If ice forms on the fan blades or a foreign object (for example, a piece of food packaging) gets there, periodic knocking or popping noise may occur when rotating.
If the evaporator freezes, the fan may touch the ice crust. The moment the blade hits the ice, a characteristic sound is heard. This is often accompanied by a decrease in cooling efficiency. In such cases, it is necessary to completely defrost the refrigerator while it is turned off within 24 hours.
It is also worth checking the fastening of the fan itself. If it is loose, the motor may vibrate and hit the plastic casing, simulating impacts. Diagnostics of this unit requires partial disassembly of the rear panel of the freezer.
☑️ Fan diagnostics
The impact of incorrect installation on acoustics
Often the source of the problem is not the internal device, but external factors. If the refrigerator is not installed level, the cabinet may be under tension. When the compressor operates, vibration is transmitted to the floor and walls, causing resonance. At a certain moment, the accumulated tension may be released with a characteristic bang.
Check the distance between the rear wall of the unit and the wall of the room. If it is too small, the condenser (black grill on the back) may expand when heated and hit the wall, making a sound. You should also make sure that the refrigerator does not touch other pieces of furniture or kitchen appliances.
Use a building level to check the horizontal installation. Adjusting the height of the legs will help stabilize the position of the case and reduce noise levels. Sometimes it is enough to simply turn the unit a little to eliminate resonance.
⚠️ Attention! Do not install the refrigerator close to the wall. The minimum distance to the back wall should be at least 5-7 cm for free air circulation and prevent overheating.
When you need to call a technician
Despite the fact that most sounds are safe, there are situations that require professional diagnosis. If the claps are accompanied by a lack of cold, a burning smell, or a buzzing sound that does not stop, you should not hesitate. This may indicate an interturn short circuit in the compressor windings or jamming of the mechanism.
Another alarming symptom is the frequent turning on and off of the motor (clocking) with a loud click. This means that the start relay is unable to start the compressor and it is trying to start again and again. In this mode, the motor can burn out in a few hours.
If you are not sure about the nature of the sound, it is better to play it safe. The technician will use a stethoscope to pinpoint the source of the noise and tell you whether it is critical. Independent repair of complex components without experience can lead to a complete loss of the tightness of the system.
Frequently asked questions (FAQ)
Why does the refrigerator slam only at night?
At night, the level of background noise in the apartment decreases, and the sounds of operating equipment become more noticeable. In addition, at night, the compressor cycles more often after long periods of inactivity, when the temperature inside the chambers has time to rise.
Is it dangerous if the door slams by itself?
If we are talking about sound and not physical movement, then it is safe. If the door actually slams itself, check the seal and the tilt adjustment of the housing. The door should open on its own if you release it at an angle of 45 degrees.
Can the sound of a bang be a sign of an explosion?
No, there is nothing to explode in household refrigerators. Freon circulates in a closed circuit under pressure, but its volume is too small for an explosion. Sounds similar to gunshots are always of a mechanical or thermal nature.
How to reduce noise from thermal expansion?
It is impossible to completely remove this sound, since this is the physics of materials. However, you can reduce its impact by making sure that the refrigerator is level and not touching the walls. Using anti-vibration pads under the legs can also help.