Faced with a situation where bubbling in the refrigerator, many owners of household appliances panic, expecting an imminent breakdown or loss of products. However, extraneous sounds do not always indicate a critical malfunction of the unit. Modern cooling systems, especially in models with No Frost, operate according to complex physical laws, where the movement of refrigerant through the tubes can create sounds reminiscent of liquid pouring or gurgling.
It is important to understand that normal operation compressor and the circulation of freon are often accompanied acoustic effects that may be confusing at first. However, there is a fine line between a normal hum and a signal that the system is depressurized or overloaded. In this article we will analyze in detail why these sounds occur, how to distinguish normality from pathology and when it is necessary to call a specialist.
If you have just installed a new unit, then active seething in the first hours of operation is absolutely normal. The circuits are initially filled with refrigerant and the pressure in the system is equalized. Refrigerant begins to actively circulate, cooling the chambers, and this process is inevitably accompanied by sound, which over time will become quieter or change its character.
Natural physical processes and circulation refrigerant
The main reason why it can bubble inside the refrigeration chamber lies in the physics of the transition of a substance from one state to another. In the closed circuit of the cooling system, freon constantly changes its state of aggregation: from liquid to gaseous and back again. It is at the moment of boiling of liquid in the evaporator or condensation of gas in the condenser that characteristic sounds of overflowing can occur.
Modern models, such as LG or Samsung, use environmentally friendly refrigerants, which can be more “noisy” when moving through narrow capillary tubes. If you hear liquid flowing after stopping the engine, this often means that the pressure in the system is equalizing. Freon flows into the lower part of the circuit, creating a gurgling effect, which is normal operation.
⚠️ Attention: If bubbling is accompanied by a sharp decrease in cooling efficiency or the appearance of an ice crust in only one corner of the chamber, this may indicate a partial blockage of the capillary tube or a gas leak.
The intensity of the sound directly depends on the amount of gas filled and the current load on the compressor. When the ambient temperature in the room is high, the system works more actively, circulation accelerates, and sounds become more distinct. Owners should listen: if the sound is monotonous and quiet, most likely, your refrigerator is simply “working.”
Features of the No Frost system
Technology No Frost (or Full No Frost) has radically changed the acoustic profile of refrigerators. Unlike the old crying models, fans are constantly running here, and the automatic defrosting system is triggered by a timer. When you hear strange bubbling or hissing, it is often the defrost system that is working.
In defrost mode, the heating element melts the ice on the evaporator, and the resulting water flows into a special tray. The process of water flowing down the drainage channels may be accompanied by sounds similar to something boiling or bubbling in the refrigerator. This is completely normal, especially if you hear it at regular intervals (usually every 8-12 hours).
Also, in systems with multiple cooling circuits (for example Multi Flow), refrigerant may be redirected between the freezer and refrigerator compartments. When switching dampers and changing the direction of gas flows, hydraulic shocks or the noise of flowing liquid are possible. Air circulation also contributes by creating a background hum that is superimposed on the sounds of the compressor.
- 🌀 The evaporator fan may hum louder if an ice coat has formed on its blades.
- 💧 The drainage system makes gurgling sounds when the ice actively melts during the defrost cycle.
- ❄️ A sharp change in pressure in the circuits when switching operating modes causes a short-term hissing.
It is worth noting that models with a fresh zone or zero chamber often use separate fans or dampers. Their operation can also be a source of noise. If the refrigerator is new, give it time (up to 24 hours) for all processes to stabilize before drawing conclusions about the malfunction.
Why is No Frost noisier than conventional models?
Refrigerators with the No Frost system will always operate louder due to the presence of fans and more frequent compressor cycles to maintain a stable temperature without the formation of ice.
The influence of improper installation and loading
Often the reason that the refrigerator began to bubble or hum suspiciously lies not in the equipment, but in the conditions of its operation. Incorrect installation is one of the most common causes of resonance and increased operating noise. If the unit body is skewed, vibration from the operating compressor is transmitted to the floor and walls, amplifying any sounds inside.
It is also important to consider the proximity to walls and furniture. The rear condenser grille requires free space for heat exchange. If the refrigerator is moved close to the wall, the hot air does not escape, the compressor begins to work with increased load, trying to compensate for overheating. In such conditions refrigerant circulates under higher pressure, which can cause whistling or intense bubbling.
Loading the chambers with products also plays a role. If the shelves are filled to capacity or, conversely, the refrigerator is completely empty, the acoustics inside change. Empty plastic containers can resonate, and tightly packed shelves prevent the normal circulation of cold air, causing the fan to work harder.
☑️ Checking installation conditions
Pay attention to the floor. If it is uneven or slippery, the refrigerator feet may not provide stable support. Adjusting the height of the feet is a simple procedure that often eliminates vibration noise completely. Use the adjusting screws located in the front lower part of the housing.
Technical malfunctions: compressor and filter drier
If natural sounds develop into a loud gurgling sound, accompanied by a lack of cold or continuous operation of the motor, this is a technical malfunction. One of the common reasons is failure compressor. When the piston group wears out or the valves lose their tightness, compression efficiency drops, and the sound of the engine changes to a duller, intermittent or, conversely, excessively loud.
Another serious problem is a clogged capillary tube or filter drier. Not only freon circulates in the system, but also special oil for lubricating the compressor. Over time, oil clots may form in the circuit or moisture may enter, which freezes in a narrow area of the capillary. This creates a blockage.
When the compressor tries to push gas through the blockage, a characteristic sound occurs, as if something is boiling or bubbling under pressure in the tubes. However, the cold does not enter the chambers, or enters very weakly. The compressor can work without stopping, trying to gain temperature, which leads to its overheating and eventual breakdown.
| Symptom | Probable cause | Sound character | Actions |
|---|---|---|---|
| Refrigerator does not freeze | Capillary clogged or freon leak | Loud bubbling, hissing | Call a technician |
| The compressor hums, but does not start | Malfunction of the starting relay | Clicks, humming, silence | Replacing the relay |
| Constant strong hum | Wear of the compressor | Vibration, low-frequency hum | Motor diagnostics |
| Periodic gurgling | Normal operation (No Frost) | Quiet flow water | Observation |
It is important not to ignore the situation when the compressor is working “pull-in”. Long-term operation in overload mode leads to burnout of the motor windings, after which repairs become economically unfeasible. A critical sign is the combination of strong bubbling and a hot back wall in the absence of cold inside.
Problems with tightness and freon leak
Refrigerant leakage is one of the most annoying problems an owner can face. If a microcrack has formed in the circuit (often in the foamed part of the body or in the places where the tubes are welded), freon begins to leave. The pressure in the system drops, and the compressor tries to compensate for this by operating longer.
When there is a leak, the circulation sound changes. Instead of a uniform hum, a whistle may appear at the gas outlet (if it is located outside) or a characteristic “plopping” sound, as air is sucked into the system. Freon When mixed with air and oil, it behaves differently, creating unstable flows, which generate strange sounds.
⚠️ Attention: You can only search for leaks on visible external tubes using a soap solution. Internal leaks in a foamed circuit can only be diagnosed by a technician using a leak detector.
If a leak occurs, there is less gas left in the system than is necessary for effective heat exchange. Residual freon can boil at a lower pressure, creating the illusion of active bubbling. However, the cooling efficiency tends to zero. The products begin to deteriorate, the chamber becomes warm, and condensation may appear on the walls.
Diagnostics and methods for eliminating noise
Before calling a technician, carry out initial diagnostics. This will help you more accurately describe the problem to a specialist and, possibly, avoid an unnecessary visit if the problem is with the settings. First of all, evaluate the nature of the sound: is it constant or periodic? Does it depend on the time of day or food load?
Check the temperature in the chambers. If the refrigerator is seething, but holds the cold perfectly, and the temperature corresponds to the set one (for example, +4°C in the refrigerator and -18°C in the freezer), then most likely the equipment is working. If the temperature is elevated and the motor is running without interruption, this is a cause for alarm.
Try to gently press the side walls or top cover with your hand when the noise appears. If the sound changes or disappears, then the problem is vibration of the case or poorly secured internal elements. Check to see if any tube is touching the back of another tube or cabinet wall.
- 🔊 Listen to where exactly the sound is coming from: from below (compressor), from behind (condenser) or from inside the chambers (evaporator/fan).
- 🌡️ Measure the temperature in the chambers with a thermometer, without relying on sensations.
- 👀 Inspect the back wall for swelling, rust or traces of oil.
If you find that the compressor is too hot (burns your hand when touched), immediately unplug the refrigerator and let it cool for several hours. Restarting may not be possible if the thermal protection has tripped, or the motor has already failed.
Prevention and operating rules
In order for your refrigerator to serve for a long time and not be disturbed by extraneous sounds, it is important to follow the operating rules. Regular defrosting (for drip systems) and cleaning the drainage hole prevents the formation of ice plugs that can disrupt the flow of water and air.
Do not place hot foods in the refrigerator. A sudden change in temperature forces the compressor to work at its limit, which accelerates wear on parts and can cause noisy boiling of the refrigerant due to sudden changes in thermal loads. Allow food to cool to room temperature before storing.
Keep the rear condenser grill clean. Dust and pet hair act as a thermal insulator, preventing heat from dissipating. Cleaning with a vacuum cleaner or brush every six months will greatly facilitate the operation of the motor and reduce the noise level.
Can a compressor be lubricated?
Modern compressors are sealed units and do not require lubrication during operation. Trying to lubricate the tube will not have any effect, and disassembling the motor will damage it.
Is it normal for the refrigerator to bubble immediately after turning it on?
Yes, this is normal. At the moment of startup, the compressor creates maximum pressure, and the active movement of refrigerant through the system causes the sounds of overflow. After 10-15 minutes, when the system reaches operating mode, the sound should become quieter.
Why did the old refrigerator begin to seethe more?
Over time, the oil in the compressor thickens, and oxidation products can accumulate in the circuit. The rubber shock absorbers under the engine could also have dried out, causing vibration to be transmitted more strongly to the body. The starting relay or oil may need to be replaced.
Is bubbling dangerous if there is cold in the chambers?
If the temperature is normal, then most likely there is no danger. This may be a feature of your model or the sound of defrosting. However, if the sound appears suddenly and is very different from the usual one, it is worth monitoring the temperature during the day.
Can bubbling be a sign of an imminent breakdown?
Burbling itself is rarely the only sign of a breakdown. It is usually accompanied by other symptoms: a long rise in temperature, continuous operation of the engine, or the appearance of puddles under the refrigerator. A comprehensive assessment of the condition is more important than one symptom.
How to reduce the seething noise without repair?
Try adjusting the legs to level the body. Make sure the refrigerator is not close to the wall. Check if the bottles on the shelves are rattling. Sometimes simply moving the unit by 1-2 cm solves the problem of resonance.