A sudden knock or periodic clicks in the operation of the refrigerator can unsettle any owner. This sound may be barely noticeable or may resemble hammer blows, especially in the silence of the night. Often, users immediately begin to panic, assuming that an expensive unit has failed and requires an immediate call to a technician.
However, there is no need to rush to conclusions. Noise diagnostics is the first and most important stage in identifying problems with household appliances. Sounds made by the compressor, pipes or housing can indicate both normal operation of the system and serious mechanical damage. Understanding the nature of these sounds will help save time and money.
In this article we will analyze in detail why the refrigerator makes clicking noises, which models are susceptible to this more often and when to sound the alarm. You will learn about the physical processes inside refrigerator compartmentthat generate sounds, and learn to distinguish the norm from a critical breakdown.
Physics of the process: thermal expansion of materials
The most common and absolutely safe reason for the appearance of extraneous sounds is physics The internal elements of the refrigerator, such as the evaporator, condenser and plastic walls, are constantly exposed to temperature changes. When cooled, materials contract, and when heated (during idle time), they expand. This process is called thermal expansion.
The plastic from which the internal panels and shelves are made has a higher coefficient of expansion than metal. When the thermostat turns off the compressor, the temperature inside begins to slowly rise. At this moment, you can hear a characteristic crackling or clicking sound. This is the sound of “playing” plastic, which begins to move relative to the metal frame.
Such sounds are especially often observed in new models, where manufacturers actively use composite materials to improve thermal insulation. Over time, the plastic “gets used” to the cycles, and the noise may become less pronounced, but it rarely disappears completely.
If the clicks are heard evenly and are not accompanied by other symptoms (for example, lack of cold or overheating of the case), then this is normal. In this case, no repairs are required.
- 🔊 The sound resembles the crackling of a fire or light tapping.
- ❄️ Clicks occur mainly when the engine is turned on or off.
- 📉 The intensity of the noise may depend on the temperature in the room.
⚠️ Attention: If the cracking noise becomes loud, sharp and accompanied by vibration, check whether the refrigerator body is touching furniture or walls. The gap between the appliances and the wall should be at least 5-7 cm.
The operation of the starting relay and electrical clicks
If the sounds are more mechanical and loud in nature, reminiscent of a blow or clanging of metal, you should pay attention to starting relay. This small but important unit is responsible for starting the compressor engine. It is the relay that supplies the impulse that starts the motor and turns off the starting winding after a set of revolutions.
At the moment the relay is activated, a distinct click is heard. In a working refrigerator it is dull and quiet. However, if the mechanism is worn out or dirty, the sound becomes loud and harsh. Often users describe this as a "thump" at the rear of the unit.
There are two main types of relays: posistor and induction. The posistor ones operate almost silently, while the induction ones (with a coil and a movable core) emit that very characteristic clanging sound. If your refrigerator is equipped with this type, then a loud click when starting is a design feature, not a breakdown.
However, if a click is heard, the motor hums for a couple of seconds, and then a click is heard again and the motor stops - this is a sign of a malfunction. In this case, it works protective thermal relay, turning off the compressor to prevent the windings from burning out. This situation requires immediate intervention.
Problems with the compressor: water hammer
One of the most serious causes of loud knocking is hydraulic hammer in the compressor. This phenomenon occurs when liquid refrigerant (freon) or oil enters the compressor cylinder at the moment the piston begins to move. Since the liquid is not compressed, the piston encounters sharp resistance, which causes a strong shock and a characteristic knock.
This often happens during startup if the refrigerator has been standing horizontally for a long time or has been moved suddenly. Oil and freon could have flowed into the circuit, from where they did not have time to drain into the compressor crankcase. Under normal conditions, the oil should be in the lower part of the engine, lubricating the rubbing parts.
If knocking noises are repeated regularly every time you start, this may indicate a violation of the refrigerant circulation or wear of the internal valves of the compressor. Sealed unit in this case, it works with increased load, which reduces its service life.
It is difficult to diagnose this problem on your own, since you need to open the system or use specialized pressure gauges. However, if the knocking is very loud and is accompanied by poor cooling, the likelihood of problems with the compressor is high.
- 💥 The sound is similar to metal hitting metal.
- 🔄 It occurs strictly at the moment the engine starts.
- 📉 Accompanied by vibration of the entire body refrigerator.
Vibration of tubes and fasteners
A refrigerator is a complex system of tubes through which refrigerant circulates under pressure. During operation, the compressor creates vibration, which is transmitted to the entire metal frame. If the copper tubes are located too close to each other or touch the housing, they begin to rattle or tap in time with the operation of the motor.
Loose fasteners can also become a source of sound. The screws that hold the compressor in place or the plastic clamps that secure the tubes in place can become loose over time due to constant vibration. This leads to play and, as a consequence, knocking.
Sometimes users themselves become the culprits of the noise, forgetting to remove foreign objects behind the refrigerator or placing heavy cans on it, which begin to rattle from vibration. Checking the area around and behind the unit is the first step in finding the source of the noise.
To eliminate the problem, it is often enough to simply move the tubes away from each other or place a piece of rubber at the point of metal-to-metal contact. The main thing is to act carefully so as not to damage the thin-walled tubes and not cause a freon leak.
Do-it-yourself fault diagnosis
Before calling a technician, you can carry out an initial diagnosis. This will help you more accurately describe the problem to a specialist, or perhaps solve it yourself. Start with visual inspection and listening.
The first thing to do is determine the frequency of clicks. Do they only happen when turned on? Or are you constantly hearing it? Is the refrigerator operating normally, cooling food? The answers to these questions narrow down the range of possible causes.
Next you should check the stability of the installation. Rock the refrigerator. If it wobbles, you need to unscrew the adjustable supports. Uneven installation is a common cause of compressor misalignment and knocking.
If you have access to the back wall (usually you need to remove a cardboard or metal panel), you can carefully inspect the tubes by turning on the flashlight. Look for places where the copper touches other parts. Also check whether the compressor itself is securely fastened to the frame.
☑️ Primary diagnostic checklist
| Sound type | Probable cause | Danger | Actions |
|---|---|---|---|
| Crackling, snapping of plastic | Thermal expansion | No | Observation |
| Loud clanging at start | Start relay | Medium | Replacement of relay |
| Metal knocking | Water hammer, compressor wear | High | Call a technician |
| Rattling | Vibration of tubes, dishes | Low | Adjust the tubes |
When you need to call a specialist
Despite the possibility of independent diagnostics, there are situations when professional intervention is inevitable. If, after eliminating external factors (vibration, instability), the clicking does not stop, and the quality of cooling has dropped, this is an alarming signal.
Particular attention should be paid to cases when the refrigerator turns on, clicks and immediately turns off. This means that the protection system is preventing the compressor from starting. Prolonged attempts to turn on such a unit can lead to engine combustion.
A technician is also needed if you hear hissing along with clicks. This may indicate a refrigerant leak. Modern models use environmentally friendly but flammable freon, so independent repair of the cooling system is prohibited.
Replacing the start relay is a simple procedure, but requires precise selection of the part. The relay parameters must strictly correspond to the compressor model. An error in selection can lead to rapid failure of the new relay or the motor itself.
⚠️ Attention: Do not try to repair a sealed circuit or replace the compressor yourself without special equipment (vacuum pump, pressure gauge station). This requires professional skills and tools.
Preventing noise and extending service life
In order for the refrigerator to please you with quiet operation for as long as possible, it is important to follow the operating rules. Regular defrosting (for drip systems) and cleaning the drainage hole prevents the formation of excess ice, which can put a strain on the system.
Do not overload the refrigerator with food. Excessive load on shelves and doors can lead to distortion of the structure and increased vibration. Distribute the weight evenly.
Keep the condenser (grid at the back) clean. Dust and animal hair accumulate on the tubes and impair heat transfer. The compressor has to work longer and harder, which increases vibration and wear of parts.
Check the door seals periodically. If they do not fit tightly, warm air enters the chamber, causing the motor to turn on more often. Frequent on-off cycles increase the number of relay clicks.
Why does a new refrigerator click louder than the old one?
New models often have more powerful compressors and an efficient, but less sound-proof design to save materials. In addition, new materials (plastic) react more actively to temperature changes at first. Over time, “grinding in” of parts reduces the noise level.
Can an inverter refrigerator click?
Inverter compressors operate smoothly and should not click during operation. However, a click is possible when initially plugged into the network or when protective systems are triggered. A constant crackling sound is not typical for an inverter and may indicate a malfunction of the electronics.
Is it dangerous to ignore loud clicks?
If the clicks are caused by thermal expansion, it is not dangerous. If the reason is the start relay or water hammer, ignoring the problem will lead to overheating and combustion of the compressor, the replacement of which costs up to 70% of the price of a new refrigerator.
Does the voltage in the network affect the appearance of clicks?
Yes, low or unstable voltage can cause the start relay to trigger multiple times, trying to start the engine, or turning it off ahead of time. To protect equipment, it is recommended to use a voltage stabilizer.