Modern refrigerators systems No Frost are designed to relieve the user of the need for regular defrosting, but they bring new sound nuances to the kitchen. If you notice that your unit has begun to make unusual sounds, hum louder than usual or click, you cannot ignore this. Extraordinary noise Often this is the first signal of an incipient malfunction or improper installation of equipment.
Unlike old drip systems, where the main work was done by the compressor, in models with function No Frost additional components operate: fans, defrost timers and complex air circulation systems. It is these components that most often become sources of hum, whistle or vibration. Understanding the physics of the processes will help you distinguish the normal operation of equipment from a critical breakdown that requires the intervention of a technician.
In this article we will analyze in detail the mechanics of noise, consider typical breakdown scenarios and explain what sounds are considered acceptable for a working device. You will learn to carry out initial diagnostics on your own and understand in which cases independent repairs can be dangerous for the compressor.
Natural operating noise: when the equipment is working properly
Many users begin to panic when they hear the first sounds after purchasing a new refrigerator, although in fact duty cycle modern equipment is rarely silent. In systems No Frost fans are constantly running, moving cold air through special channels, which creates an even background hum. This is absolutely normal, especially if you are used to the silence of older models.
It is also worth considering the physical behavior of the refrigerant. When passing through the capillary tube and expansion valve, freon changes its state of aggregation, which is often accompanied by sounds reminiscent of gurgling water or quiet hissing. Gas circulation can be heard even after the compressor is turned off, until the pressure in the system is completely equalized.
Particular attention should be paid to the thermal expansion of materials. The plastic of the internal housing and the metal elements of the evaporator may produce a cracking sound similar to clicks when there is a sudden change in temperature. If the refrigerator is on an uneven floor, these vibrations can intensify, creating the illusion of a serious breakdown, although in reality it is simply the physics of solids.
⚠️ Attention: If the hum intensifies over time or metallic clangs are added to it, this is no longer an operating noise, but a sign of wear on the components.
It is important to learn to distinguish the character sounds. The even hum of the motor, the periodic quiet hiss of freon and rare clicks of the thermostat are signs of the health of your No Frost unit. You should worry only when the nature of the sound changes to sharp, intermittent or is accompanied by vibration of the case.
Problems with installation and ventilation of the compressor
One One of the most common reasons why a refrigerator hums louder than usual is a banal violation of installation rules. If the body of the equipment touches the wall, furniture or adjacent cabinets, the vibration from the operating compressor is transmitted to these surfaces, acting as a resonator. As a result, a quiet hum turns into an obsessive low-frequency rumble.
It is critical to maintain the gap between the back wall of the refrigerator and the wall of the room. The system No Frost requires efficient heat removal from the condenser (black grille at the back). If the gap is less than 5-7 centimeters, the air circulates poorly, the motor overheats and begins to work with increased load, which inevitably leads to an increase in noise level.
Also check the horizontal installation. If the refrigerator is not level, the compressor may vibrate more than usual. To adjust, use the front legs, twisting them until the body stops wobbling and the doors begin to close on their own when slightly opened.
☑️ Checking the installation of the refrigerator
Another nuance - transportation bolts. In some models, the compressor is secured with bolts for transportation, which must be unscrewed before turning on for the first time. If this is not done, the motor will hang on rigid mounts, transmitting vibration to the entire body, which will lead to rapid wear and loud noise.
No Frost system fan malfunctions
The heart of the system No Frost is the fan, which provides forced circulation of cold air. It is this node that most often becomes the source of whistling, howling or crackling. If you hear that the noise is not coming from the bottom (where the compressor is), but from inside the chamber or from behind the back panel, the problem most likely lies in the fan impeller. Over time, the fan motor bearings dry out and wear out. This results in a characteristic howling sound that may appear and disappear. In more advanced cases, the blades begin to touch frozen ice or structural elements, producing a loud crack or knock, similar to the operation of a propeller. fan impeller.
Over time, fan motor bearings dry out and wear out. This results in a characteristic howling sound that may appear and disappear. In more advanced cases, the blades begin to touch frozen ice or structural elements, producing a loud cracking or knocking sound similar to the operation of a propeller.
Ice is also a frequent cause of noise. If the defrost system is not working properly, ice can build up on the evaporator and get into the rotating blade area. In this case, you will hear an intermittent knocking sound. Also, a small object or piece of packaging could get into the air duct opening, which begins to hit the walls when the air rotates.
⚠️ Attention: Long-term operation of a fan with damaged bearings can lead to jamming of the motor and burnout of the winding.
For diagnostics, it is often necessary to remove the back panel in the freezer. A visual inspection will show the presence of ice on the blades or shaft play. In some cases, bearing lubrication helps, but most often a complete replacement of the assembly is required, since modern fans are often produced in a non-separable housing.
How to check the fan without disassembling?
Turn on the refrigerator and open the freezer door. On many models, the fan stops when the door is opened. If the noise disappears immediately after opening, the problem is definitely there.
Compressor noise: from hum to knocking
The compressor is the most expensive and important component of the refrigerator. In its normal state, it emits a monotonous hum, but a change in tone or the appearance of extraneous sounds indicates problems. If you hear a loud metallic knock or clang, this may indicate that motor mounting the inside of the casing has failed and the "heart" of the refrigerator is beating against the metal walls.
Water hammer is another dangerous cause of noise. It occurs if liquid freon instead of gaseous freon enters the compression chamber of the compressor. This is accompanied by a sharp, loud bang or series of knocks upon startup. This often happens when the thermostat or sensors malfunction, when the refrigerant does not have time to evaporate in the evaporator.
It is also worth paying attention to the start relay. If, when you try to start, you hear a loud click, followed by a hum for a couple of seconds and then another click (stop), then the engine cannot start. This may be due to a voltage drop in the network or an interturn short circuit of the windings of the compressor itself.
The table below shows the main types of noise of the compressor group and their probable causes:
| Sound type | Probable cause | Degree danger |
|---|---|---|
| Monotonous hum | Normal operation | Safe |
| Metal clanging | Destruction of the internal suspension | High |
| Sharp bang at start | Water hammer (liquid freon) | Critical |
| Clicks and buzzing 3-5 sec | Malfunction of the starting relay | Medium |
The influence of ice and the defrost system
System No Frost ("no frost") does not mean a complete absence of ice inside the unit. It is formed on the hidden evaporator and then removed by the heating element. If the defrost cycle is disrupted, the ice begins to grow uncontrollably, turning into a huge block. This mass of ice becomes a source of various sounds.
When the fan is running, ice can break off and fall to the bottom of the chamber or get stuck in the blades, causing a knocking sound. In addition, the defrosting process itself is sometimes accompanied by sounds. When the hot heating element begins to melt the ice, you may hear a hissing or even a crackling sound, similar to gunshots. This occurs due to a sharp temperature change and cracking of the ice crust.
If the drainage hole is clogged with debris or frozen, water from melting ice does not go into the pan, but accumulates below. During the next cooling cycle, this water freezes, increasing in volume and creating pressure that can deform plastic parts or cause squeaks during expansion.
⚠️ Attention: A thick layer of ice on the evaporator not only makes noise, but also makes the compressor work longer, increasing energy consumption.
Regular, at least once a year, full defrosting the refrigerator (even the system No Frost) helps prevent these problems. This allows you to clean the drainage and make sure that there are no excess ice build-ups inside the chambers that interfere with air circulation.
Foreign objects and resonance of dishes
Sometimes the cause of the noise is trivial and is located on the surface. Vibration from the operation of the unit is transmitted to the shelves installed inside and to objects standing nearby. Glass shelves, if they are not secured tightly in the grooves, may rattle. The same goes for plastic containers, bottles of liquid, or cans that touch each other.
Check the contents of the refrigerator. Empty glass bottles standing nearby begin to ring at the slightest vibration. Metal pallets touching the gratings create an unpleasant high-frequency ringing. Simply move the objects apart or place a soft cloth under them to eliminate the noise.
Also inspect the space around the refrigerator. Boxes of cereals, jars or kitchen utensils are often stored on the back wall. The vibration of the body causes these objects to move and rattle. Make sure that nothing touches the rear radiator grille or the side of the body itself.
The dishes inside the chambers deserve special attention. Heavy pots on glass shelves may move. If the shelf has rubber stops, check their integrity. The absence of rubber bands leads to direct contact of the glass with the metal support, which enhances the resonance.
Diagnostics and methods for eliminating noise
Before calling a technician, conduct your own diagnostics. It will help save time and money. Start with visual inspection and listening. Place your ear on different parts of the case (being careful) to localize the source of the sound: top, bottom, back wall or inside.
Try to gently press the vibrating panel or door with your hand. If the noise disappears, then the problem is vibration of the plastic or loose fitting of the elements. In this case, gaskets or adjusting screws can be used. If the sound comes from the motor and is accompanied by heating, it is better not to risk it.
To eliminate fan noise, it is sometimes necessary to lubricate it, but this is a temporary measure. Modern motors often do not have oil holes. The only reliable way is to replace the node with a new one. Similarly with the compressor: if it starts knocking, no amount of external lubrication will help, complex repairs are required with soldering pipes and replacing the unit.
Independent soldering of pipes without evacuation of the system will lead to moisture ingress and rapid failure of the equipment.
Why does the refrigerator make the sound of a bursting bubble or pouring water?
This sound is absolutely normal for a working refrigerator. It is caused by the movement of refrigerant (freon) through the system pipes. When gas passes through narrow sections of a capillary tube or expands in an evaporator, an effect similar to boiling or pouring of a liquid is created. The sound can be heard even when the compressor is turned off, as the pressure in the system gradually equalizes.
Is it normal if the refrigerator hums only at night?
Yes, this is a common occurrence. During the day, the background noise of the kitchen, TV and conversations masks the operation of the equipment. At night, in silence, the same sound level (usually 36-40 dB) becomes noticeable. In addition, at night the voltage in the network may drop, which forces the compressor to work with a slightly higher load, or its switching cycle simply coincides.
Can an old refrigerator start to make more noise?
Certainly. Over time, fan bearings wear out, rubber shock absorbers under the compressor dry out, and panel fastenings become loose. Dust accumulation on the rear of the condenser also impairs heat transfer, causing the motor to work harder and louder. Regular cleaning and maintenance prolong quiet operation.
What should you do if, after defrosting, the refrigerator begins to make noise?
If noise appears immediately after defrosting, perhaps you did not dry the chambers well enough or water got into the drainage hole, which froze and interfered with the operation of the fan. The operating mode could also be lost, and the system needs time (up to 24 hours) to stabilize temperature conditions. If the noise does not go away for a day, contact the service.