The appearance of extraneous sounds in household appliances always causes concern for the owner, and clicks in the refrigerator are no exception. Often these sounds signal the onset of serious problems that can lead to food spoilage and costly repairs. However, do not panic ahead of time, since the nature of the noise can be either completely natural or critical.
In this article we will analyze in detail the mechanics of the cooling circuit so that you can independently determine the source of the problem. Understanding the physical processes occurring inside the unit will help distinguish the normal operation of the equipment from a breakdown that requires the intervention of a technician. We will look at the main components responsible for starting and stopping the engine, as well as thermal expansion of materials.
Natural physical processes and thermal expansionMany users mistakenly believe that a working refrigerator should operate absolutely silently, but this is not entirely true. During the cooling and heating process, internal elements of the case, such as plastic lining and metal evaporator tubes, undergo thermal deformation. Thermal expansion materials inevitably occur when the surface temperature changes by several degrees.
These changes cause a characteristic crackling or clicking sound, which is especially noticeable in the quiet of the night. The sounds may resemble the crackling of plastic or the slight clinking of metal, and they do not pose any threat to the functionality of the device. Typically, such sounds occur at moments when the compressor has just stopped or, conversely, started its operation, sharply changing the temperature regime of the internal chambers.
If you notice that clicks are heard irregularly and are accompanied by normal operation of the refrigeration chamber, then most likely there is nothing to worry about. It is important to listen to the nature of the sound: natural expansion is produced as a quick, single crackling sound, and not as a rhythmic knocking of a mechanism. In most cases, owners of new models notice these sounds more strongly due to better sound insulation, which makes extraneous noise more contrasting.
⚠️ Attention! If clicking sounds are accompanied by a burning smell, smoke or sparking inside the housing, immediately unplug the device from the power supply and call a specialist. This may indicate a short circuit or overheating of the wiring.
Operation of the start-up relay and start capacitor
One of the most common technical causes of clicking is the operation of start protection relay. This small but critical element is responsible for supplying voltage to the compressor motor windings at startup. When you hear a click, it often means that the relay is trying to start the motor, but is encountering resistance or an overload.
In normal operation, the relay makes one clear click when the compressor turns on and another (sometimes less audible) when it turns off. However, if the device is worn out or there are power surges in the network, the relay may begin to “crack”, making a series of rapid clicks. This indicates that the mechanism is trying to start the engine repeatedly, but the protection is triggered, breaking the circuit.
It is also worth paying attention to starting capacitor, which helps the engine gain the necessary speed. If the capacitor has lost its capacity, the load on the relay increases, which leads to increased clicking. In some models of refrigerators, especially old ones, the relay is made in the form of a separate box attached to the compressor housing, and its replacement does not require complex tools.
Relay diagnostics are often carried out by elimination. If, when removing the relay and shaking it, you hear the ringing of internal parts, this is a sure sign of destruction of the core or contacts. In such cases, the part must be replaced, since its further operation can lead to combustion of the compressor windings.
Compressor malfunctions: valve knocking and wear
The heart of any refrigerator is the compressor, and if clicks come directly from it, the situation can be serious. Inside the sealed casing there are valves that control the circulation of the refrigerant. When the valve group wears out or there is play in the motor mounts, metallic knocks may occur, which users often describe as clicking.
A particularly alarming symptom is the situation when a loud click is heard, after which the refrigerator hums for several seconds and clicks again, but does not start. This is a classic picture compressor wedge or failure of its mechanical part. The motor tries to turn over, but due to a mechanical obstacle or lack of lubrication it jams, and the thermal protection emergency cuts off the power.
In some cases, clicks can be caused by vibration of the compressor body itself against metal tubes or cabinet walls. If the mounting bolts or rubber shock absorbers are worn out, the engine begins to “walk” when starting, hitting adjacent elements. This is not an electronic failure, but requires immediate attention as repeated impacts can lead to (ruptured) pipes.
| Sound type | Probable cause | Repair needed | Risk to products |
|---|---|---|---|
| Single quiet click | Thermal relay or thermal expansion | Not required | Absent |
| Series of quick clicks | Starter fault relay | High | Medium (risk of defrosting) |
| Loud metallic knock | Compressor wear | Critical | High |
| Clicking and buzzing without starting | Compressor wedge or break | Replacing the unit | Critical |
⚠️ Attention! Attempting to open the sealed compressor casing yourself is strictly prohibited. Inside there is oil and refrigerant under pressure, and repairs require special equipment and skills.
Problems with the No Frost system and fans
In refrigerators equipped with the system No Frost, air circulation is carried out using fans. If you hear clicking noises coming from the freezer compartment or the top of the refrigerator compartment, the fan may be the source. The blades may touch ice formed due to a leak or a malfunction of the defrost system.
When ice builds up on the channel walls, it partially blocks the path of the blades. When rotating, the fan periodically hits the ice crust, which is perceived as a rhythmic knock or click. Over time, the frequency of these sounds may increase until the blades become damaged or the fan motor jams.
Another reason may be the fan itself being unbalanced or its bearings worn out. In this case, the sound will be more like friction or an intermittent hum with a metallic tint. For diagnostics, it is often necessary to remove the back panel in the freezer and visually inspect the condition of the blades and the presence of ice.
☑️ Diagnostics of the No Frost system
It is important to note that in models with a freshness zone, additional small fans can also be installed. Their malfunction also produces characteristic clicks, but they are usually less loud than the sounds of the main motor of the No Frost system. Regular defrosting helps prevent the formation of excess ice and prolongs the life of these mechanisms.
Electric clicks of the thermostat and sensors
Thermostat (thermostat) is a device that controls the temperature inside the chambers and gives the command to turn the compressor on or off. Inside this device there are electrical contacts that open and close with a characteristic click. This is an absolutely normal operating sound, indicating that the automation is functioning correctly.
However, if the clicks of the thermostat become too frequent (the refrigerator constantly turns on and off), this indicates an incorrect setting or a malfunction of the sensor. This phenomenon is called a “short cycle”, and it is extremely harmful for the compressor, since it does not have time to cool down between starts. Starting frequency should not exceed 4-6 times per hour under normal conditions.
In modern models with electronic control, the role of a mechanical thermostat is performed temperature sensors and control module. In this case, clicks may be produced by the relay on the control board. If the electronics “glitch” due to a power surge or humidity, it can send chaotic signals to start, which will be accompanied by a series of clicks.
How to check the thermostat?
To mechanically test the thermostat, you can close its contacts directly (bypassing the regulator itself). If after this the compressor starts and runs continuously, then the problem is in the thermostat and it needs to be replaced. Be careful when working with electricity!
Sometimes users confuse the clicks of the thermostat with the sounds of plastic deformation, but they are easy to distinguish: the click of contacts is always accompanied by a change in operating mode (starting or stopping the motor), while the cracking of plastic occurs chaotically. If clicks are heard precisely at the moment when the operation indicator lights up or goes out, the source is in the electrical control circuit.
External factors: installation and environment
The cause of clicks does not always lie inside the unit itself. Incorrect installation of the refrigerator can lead to resonance phenomena. If the housing is not level, vibration from the operating compressor is transmitted to the floor and walls, causing rattling and clicking of the contacting surfaces. Checking the horizontal installation is the first place to start diagnosing.
You should also pay attention to the proximity of the refrigerator to other pieces of furniture or household appliances. When the motor is running, the housing may vibrate slightly and touch a nearby cabinet or wall, producing rhythmic tapping sounds. It is enough to simply move the refrigerator a couple of centimeters to eliminate this effect.
Unstable power supply in the house is another important external factor. If the mains voltage drops below the permissible limit, the starting relay may not be able to start the engine, making frequent clicks. In areas with poor power supply, it is recommended to use voltage stabilizers to protect expensive equipment.
⚠️ Attention! Do not install the refrigerator close to a wall or furniture. For normal air circulation around the condenser (grid at the back), a gap of at least 5-10 cm is required.
When you need to call a technician: critical symptoms
There are a number of symptoms in which self-repair is not only ineffective, but also dangerous. If, after a series of clicks, the refrigerator does not start, but the light is on inside, this may indicate an interturn short circuit in the compressor windings. In this case, the motor hums, but does not rotate, and after a while a protective click is heard.
If you observe that clicks are accompanied by heating of the compressor housing to very high temperatures (impossible to touch with your hand), this is a sign of overload. Operating the device in this mode will lead to complete combustion of the engine and the need for an expensive replacement. Timely contacting a specialist at the first sign of a compressor wedge can save the unit.
A specialist is also needed if the clicks come from inside the sealed circuit or if you do not have experience working with electrical appliances and a multimeter. Diagnosing an electrical circuit requires accuracy, and an error can lead to electric shock or further damage to the refrigerator's electronics.
Frequently asked questions (FAQ)
Why does the refrigerator click but does not freeze?
This is a classic sign of a faulty start relay or compressor. The relay tries to start the engine (click), but due to a breakdown the motor does not start, and the thermal protection is triggered (second click). Diagnosis and replacement of the faulty element is required.
Is it normal for the refrigerator to click immediately after defrosting?
Yes, after defrosting and turning on, more active thermal expansion of materials may be observed, which causes a cracking sound. Also, the compressor may work harder to build up temperature, which increases the load on the start relay.
Can a new refrigerator click?
New refrigerators may make sounds of thermal expansion of plastic and metal, which is normal. However, there should be no mechanical relay clicks or compressor knocking in a working new device.
How to distinguish a thermostat click from a relay click?
The thermostat click usually occurs less frequently (when the set temperature is reached) and sounds duller. The clicks of the start relay are louder, more frequent and occur when you try to start the engine.
Is it dangerous to ignore clicks in the refrigerator?
If the clicks are natural (thermal) - no. But if these are signals of a relay or compressor malfunction, ignoring them can lead to complete failure of the unit and damage to products. It is better to carry out a diagnosis at the first symptoms.