A sudden extraneous sound in the operation of household appliances always causes alarm. The situation when a knock is heard, reminiscent of the fall of heavy objects, can confuse even an experienced owner. Most often, it is too early to panic, since the nature of this noise can be completely harmless. refrigerator there is a knocking sound reminiscent of heavy objects falling, which can confuse even an experienced owner. Most often, it is too early to panic, since the nature of this noise can be completely harmless.
However, you cannot ignore the signal. Sharp knocks inside the housing or a characteristic clanging sound when starting the motor sometimes indicate serious malfunctions compressor or the defrost system. Understanding the physics of the process will help you quickly determine whether you need to call a technician or the problem can be solved yourself in five minutes.
In this article we will analyze in detail all the possible causes of sounds that simulate falling objects. You will learn to distinguish normal operation of the freon system from critical breakdowns that require immediate attention.
⚠️ Attention: If the knocking is accompanied by a lack of cold, flashing indicators or a burning smell, immediately disconnect the device from the network. Further operation may lead to complete failure of the unit.
Natural physical processes and operation of the defrost system
The most common cause of strange sounds lies in the normal operation of the equipment. Modern models, especially those with No Frostsystem, are equipped with automatic defrosting cycles. During the defrosting process, the ice accumulated on the evaporator melts, and pieces of ice can fall into a special tray.
It is this sound - the dull impact of ice on the plastic bottom or metal elements - that users most often describe as “something dropped”. This is absolutely normal for technology, where air circulation is forcibly organized. The sound can be loud if the ice block was large.
In addition, the thermal expansion of materials also makes its own adjustments. The plastic of the inner walls and metal tubes heat exchanger can make cracking or clicking noises when the temperature changes sharply. These sounds often resemble the pouring of small objects or light impacts.
- 🧊 Falling ice: A characteristic loud or dull knock during the defrosting cycle.
- 🌡️ Thermal expansion: Crackling of plastic and metal when temperature changes modes.
- 💨 Refrigerant movement: Gurgling and flow of liquid in the tubes, which sometimes ends with water hammer.
It is important to note that the intensity of these sounds may depend on the build quality of a particular model refrigerator. In some budget series, the resonance of the case enhances the natural noise of the mechanisms.
⚠️ Attention: Technical characteristics and noise levels may vary depending on the manufacturer and year of manufacture of the model. Always check the user manual for your device to determine acceptable sound pressure levels.
How to distinguish normal noise from a breakdown?
The normal defrosting sound occurs periodically (once every 8-12 hours) and does not last long. If the knocking noise is repeated every few minutes or is accompanied by vibration of the entire housing, this is a sign of a malfunction.
Problems with the compressor mount and motor
If the sound is heard in the lower part of the unit and is more like a metallic clanging sound when starting, the problem may lie in compressor. This is the “heart” of the refrigerator, and its operation should not be accompanied by impacts on the body. Often the cause is loosening of the mounting bolts or wear of the rubber shock absorbers.
When starting, the motor jerks, and if it is poorly secured, the metal part hits the frame or casing. Over time, the vibration only intensifies, which can lead to pipe breakage freon pipes. In this case, the sound really resembles the fall of a heavy instrument.
It is also worth checking the condition of the suspension of the compressor itself. Older models used springs that could stretch or slip over time. Then motor begins to dangle inside the casing, creating a characteristic rumble with each switching cycle.
- Visually inspect the bottom of the refrigerator (you need to remove the back panel).
- Check the tension of the springs and the condition of the rubber bushings under compressor.
- Make sure that the tubes do not touch each other and the walls of the housing.
To fix the problem, it is often enough to tighten the nuts or replace worn rubber gaskets. If the winding or internal mechanics of the motor are damaged, the entire assembly will need to be replaced.
☑️ Diagnostics of the compressor compartment
Fan and No Frost system malfunctions
In refrigerators with a system No Frost the fan is responsible for circulating cold air. If its blades begin to touch ice or a foreign object, a rhythmic knocking or cracking sound occurs. It may seem to the user that something has fallen off inside the chamber and is dangling.
A common cause is ice freezing on the fan axis or in the air duct. The blades, rotating at high speed, hit the ice crust. The sound can be very loud and frightening, especially at night. In such cases fan requires defrosting.
Another option is failure of the fan motor bearing. In this case, a hum appears that turns into knocking. The motor begins to play, and its body hits the plastic mounting socket. This requires replacement of the unit.
| Symptom | Probable cause | Solution method |
|---|---|---|
| Rhythmic crackling | The blades touch the ice | Complete defrosting (24 hours) |
| Humming noise | Bearing wear | Fan replacement |
| Intermittent noise | An outsider has entered item | Inspection and cleaning of the chamber |
It is worth remembering that in some models refrigerators two fans can be installed: one in the freezer compartment, the other in the refrigerator compartment. To localize the source of the sound, turning off the nodes one by one (for the pros) or analyzing the area where the noise is coming from will help.
Foreign objects and improper loading
Before committing a breakdown, you should rule out trivial causes. Often the sound of a falling object is made by the products themselves. Glass bottles touching when shelves vibrate, or heavy pots can create the illusion of equipment malfunction.
Particular attention should be paid to glass shelves. If they do not fit tightly in the guides or have a manufacturing defect (microcracks), during vibration compressor they can shift and hit the walls. The sound is very similar to the fall of a heavy stone.
Also check the space behind the refrigerator. Often small things accidentally end up there: coins, keys, children's toys. When the motor operates, vibration is transmitted to the floor, and these objects begin to bounce, creating a clattering sound. In addition, the refrigerator itself may not be level, which increases the resonance.
- 🥤 Products: Check the stability of bottles and containers on the shelves.
- 🍽️ Dishes: Make sure the plates are not touching each other.
- 🧱 Shelves: Adjust the glass surfaces in the grooves, check the integrity of the plastic.
Sometimes users forget to remove the packing tape or shipping bolts (although the latter usually interfere with starting the unit for the first time). Any extra object inside the cameras can become a source of noise.
Pipeline defects and water hammer
The refrigerant circulation system is a closed loop of metal tubes. When passing freon through the capillary tube and expansion valve, a water hammer effect may occur. The liquid phase of the refrigerant noisily rushes into the low-pressure zone.
If the tubes are not secured tightly enough or, on the contrary, have too much play, they can hit each other or the housing. The sound is metallic, ringing, sometimes reminiscent of falling nuts. This often occurs after transportation or poor-quality repairs.
In rare cases, an air lock or blockage may form in the system, which changes the nature of gas movement. Refrigerant begins to move jerkily, causing vibration and shocks in the pipeline. This requires the intervention of a specialist with a pressure manifold.
It is difficult to diagnose the problem of the tubes without opening the casing. However, if you hear a distinct metallic clang just when the engine has just started or is about to stop, the likelihood of contact between the pipes is high.
⚠️ Attention: Independent intervention in the pipeline system is prohibited. This can lead to freon leakage and a leak in the circuit. To straighten the tubes, call a specialist.
When it is necessary to call a technician: critical signs
Not all sounds are safe. There are a number of signs indicating that refrigerator requires urgent professional repair. If you ignore these signals, restoring the equipment may become economically unfeasible.
First of all, pay attention to the operating cycle. If the knocking is accompanied by the motor turning on for a couple of seconds, clicking and turning off (protective relay), but the cold does not build up, this is a sign of a breakdown of the compressor or start relay. Here, the sound of a “fall” may be the sound of the protection being activated or the impact of the piston group.
Also an alarming signal is a change in the nature of the sound over time. If the quiet hum has grown into a constant roar, and the temperature inside the cells has risen, you cannot hesitate. Failure compressor is often sudden and noisy.
- 🔥 Motor heating: The compressor has become hot to the touch and vibrates strongly.
- 📉 Lack of cold: Products begin to deteriorate, indicators flash.
- ⚡ Frequent starts: The motor runs jerkily with loud clicks.
Remember that modern inverter compressor It works quieter than usual, but its diagnostics are more difficult. Any deviations from the normal mode in such models require computer diagnostics.
Why does the refrigerator make the sound of a falling stone only at night?
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, the network voltage is usually lower at night, which can change the way the engine starts. Also, at night, an automatic defrosting cycle occurs more often if the refrigerator is set on a timer.
Can a new refrigerator knock?
Yes, during the break-in period (the first 2-3 weeks), new mechanisms may make louder sounds. The new models also feature more active ventilation systems. If the knocking does not go away after a month and gets worse, contact the service center under warranty.
Is it dangerous to continue using the refrigerator if it is knocking?
If the knocking is caused by falling ice (No Frost) - it is not dangerous. If the compressor or fan is knocking, prolonged operation will lead to their complete destruction. In the case of a compressor, it may become wedged, after which an expensive replacement will be required.
How to quiet a noisy refrigerator yourself?
Try to level the legs of the refrigerator. Make sure it does not touch the wall or furniture. Check the shelves for items that may vibrate. If these measures do not help, diagnostics of the internal components is required.