The situation when the refrigerator clicks during operation is familiar to many owners of household appliances. This sound can be barely audible, barely noticeable against the background of a general hum, or sharp, frightening, echoing into the walls of the kitchen. Extraneous noise often becomes the first signal that changes are occurring in the cooling system that require attention. However, there is no need to panic ahead of time: not every click means a critical breakdown.
Modern units, be it Indesit, Bosch or LG, have a complex design where many parts interact with each other. The metal expands when heated and contracts when cooled, electrical contacts open and close, and the refrigerant changes its state of aggregation. All these processes can be accompanied by sound effects. In this article, we will analyze in detail the physics of these phenomena and help distinguish normal operation from the harbingers of serious repairs.
Natural physical processes: thermal expansion
The most common and absolutely safe cause of clicking is thermal deformation of materials. The inner walls of the chamber, the evaporator and the outer casing are made of plastic and metal, which have different coefficients of thermal expansion. When the compressor starts and begins to actively cool the chamber, the temperature of the parts drops sharply. When the motor stops, the reverse process occurs - heating.
These cyclic changes cause microscopic displacements of the layers of material relative to each other. It is at this moment that a characteristic crack or single click is heard. Thermal expansion is a normal physical phenomenon that is observed in all models, including premium Samsung and budget Atlant. This process can be heard especially loudly in new refrigerators or after a long defrost, when the equipment returns to operating mode.
Often users notice that the clicking intensifies when the temperature in the room changes or after loading a large amount of warm food. In such cases, the system operates under increased load, temperature changes become sharper, and the “background sound” increases. If the sound resembles the crackling of a fire or occasional blows on plastic, there is most likely nothing to worry about.
⚠️ Attention: If the clicks are accompanied by the appearance of an unpleasant smell of burning or melted plastic, immediately unplug the device. This may indicate overheating of the wiring, which is not the norm.
It is worth considering that the design of some models involves a tighter fit of the panels, which can increase resonance. Over time, as the materials “grind” against each other, the intensity of the sounds may decrease, but they rarely disappear completely. This is a feature of operation, not a defect.
Operation of the start-up relay and electrics
The second most common source of sounds is the electrical part of the refrigeration unit. A special device, the start-protection relay, is responsible for starting the compressor engine. Older models used posistor or electromagnetic relays, which made a loud, audible click when activated. In modern inverter systems, this process is quieter, but can still be heard.
When the thermostat or electronic control board commands to start, voltage is applied to the relay coil, the contacts close, and a click is heard. A similar sound, but sometimes quieter, occurs when the circuit opens when the desired temperature in the chamber is reached. Start relay is a mechanical switch, and its operation is always accompanied by sound. If the refrigerator clicks once when starting and once when stopping, this is normal operation.
However, there is a nuance that requires diagnostics. If you hear a series of quick clicks, after which the motor hums for a few seconds and then clicks again, followed by silence, this is an alarming symptom. This situation indicates that the start relay is trying to start the compressor but is unable to do so. The reasons may lie in:
- 🔌 Failure of the starting relay itself (the winding burned out or the contacts were stuck).
- ⚡ Interturn short circuit in the compressor motor windings.
- 📉 Critical voltage drop in the electrical network apartments.
In such cases, the motor does not start, the refrigerator does not cool, and it becomes warm inside the chamber. Prolonged attempts to start can lead to the compressor burning out, so if you have the described symptoms, it is better to call a technician.
How to check the relay yourself?
To check the relay, it must be removed from the compressor. If, when shaking inside, a knocking sound is heard (as if from broken ceramics), it means that the posistor or mechanical part is damaged and requires replacement.
It is important to note that in models with the system No Frost electrical clicks can also be produced by defrost sensors or valves that switch refrigerant flows, although this happens less frequently and sounds otherwise.
Problems with the compressor: water hammer and wear
The compressor is the heart of the refrigerator, and its operation is not always silent. The internal structure of the pump motor includes pistons, valves and springs. During normal operation it emits a steady hum. However, if you hear metallic clicks, clanging or knocking, this may indicate internal problems with the unit.
One of the reasons may be hydraulic hammer. It occurs if liquid freon (which did not have time to evaporate in the evaporator) enters the compressor cylinder. Since the fluid is not compressed, the piston encounters resistance as it moves, causing a dull thud or click. This often happens when the refrigerator is not properly charged or the operating temperature is violated.
Also, the source of the sound can be wear of the internal shock absorbers. The motor is suspended inside the casing on springs to dampen vibrations. Over time, the metal gets tired, the springs can burst or jump off, and then when starting the motor will hit the walls of the casing. This causes a loud clanging sound in the first seconds of operation.
| Sound type | Probable cause | Criticality |
|---|---|---|
| Single click at start/stop | Relay or thermostat | Normal |
| A series of clicks, the motor does not start | Faulty relay or starting winding | High |
| Metallic clanging inside motor | Wear of the piston group | Critical |
| Crackling sound similar to boiling | Movement of freon through the tubes | Normal |
Diagnostics of the compressor requires professional skills and tools. It is strictly forbidden to open the motor casing on your own due to high pressure and the presence of oil.
No Frost system and defrosting: what happens inside
Owners of refrigerators with the system No Frost often encounter clicks that come from the back wall or top of the unit. These sounds are related to the operation of the automatic defrost system. Periodically, according to a timer signal, the heating element (heating element) turns on, which melts the ice on the evaporator.
At this moment you can hear:
- 🧊 The crackling sound of bursting ice (similar to clicks).
- 💧 The sound of dripping water in pan.
- ⚡ Click to switch the air duct damper.
These processes can be heard especially loudly at night, when the apartment is quieter. The sound may sound like gunshots or hitting plastic. This occurs due to a sharp temperature change: the ice melts, the plastic is deformed, and a sound is heard. In models Indesit and Ariston this occurs quite often and is considered a variant of the norm.
Also in the system No Frost a refrigerant switching valve is installed (in two-compressor or complex single-compressor circuits). It can click, redirecting the flow of freon between the freezer and refrigerator compartments. This sound is usually dull and occurs once every 20-40 minutes.
⚠️ Attention: If clicks in No Frost mode are accompanied by the appearance of ice in the chamber or water on the floor, the drainage system may be clogged or the defrost timer is faulty.
Understanding the operating cycles of your refrigerator will help distinguish normal defrosting from failure. Typically, these sounds last no more than 15-20 minutes and are repeated at certain intervals (every few hours).
Thermostat and temperature sensors
A mechanical thermostat is another source of sounds. Inside it is a bellows tube filled with gas or liquid that reacts to changes in temperature. When the temperature in the chamber reaches the set value, the contacts inside the thermostat open with a characteristic click, turning off the compressor. When the chamber heats up, the process is repeated in the reverse order.
The more accurately the temperature is set and the narrower the hysteresis range (the difference between turning on and off), the more often the thermostat can click. In old models this sound was very loud, modern analogues are quieter, but still audible. Temperature sensor in electronic models it works silently, but the executive relay on the control board, which is also located inside the case, can click.
If the thermostat clicks begin to sound too often (for example, every 2-3 minutes), this indicates that the refrigerator does not keep cold. The reasons may be:
1. The door seal is broken.
2. Clogged condenser (radiator at the back).
3. Lack of freon in the system.
In such a situation, the equipment operates in emergency mode, trying to compensate for heat inflows, which leads to excessive energy consumption and wear of the compressor.
Diagnostics and user actions
What to do if you hear suspicious sounds? The first step should be initial diagnostics, which can be carried out independently without disassembling the unit. This will help the technician over the phone to more accurately determine a possible malfunction and determine the cost of the work.
First of all, listen to the nature of the sound and its frequency. Try to localize the source: is the sound coming from below (compressor), from inside the chamber (thermostat, ice) or from behind (relay, capacitor). It is also important to check the operating conditions: is the refrigerator standing level, is it not touching walls or furniture, which can increase vibration.
☑️ Primary diagnostic checklist
If you find that the refrigerator is standing crooked, be sure to level it using the adjustable feet. The vibration of a skewed case is often transmitted to internal parts, causing them to collide and click. Also check if the shelves or drawers are loose - sometimes it is they that ring or click, and not the mechanism.
If simple measures did not help, and the sound causes concern (especially if it is a series of clicks without starting the motor), it is better not to risk it. Operating a faulty unit can lead to more expensive repairs.
When you need to call a technician
Not all clicks require the intervention of a specialist, but there are situations where delay is dangerous. If you notice that the refrigerator clicks, but does not freeze, or freezes weakly, and there is no characteristic heating on the rear grille (condenser), this is a sign of a serious malfunction.
You also need professional help if:
- 🔥 There is a smell of burnt insulation or plastic.
- 💡 The light inside is on, but the motor is silent or hums and clicks without starting.
- 🌡 The temperature in the chambers no longer corresponds to the settings.
- 🔊 The sound has become metallic, ringing and constant.
The master will carry out diagnostics of the electrical circuit, checks the resistance of the compressor windings, freon pressure and the condition of the starting equipment. Repairs can range from replacing a cheap relay to a complex system refill or replacing a compressor.
⚠️ Warning: Do not attempt to disassemble a sealed circuit yourself or change a compressor without special equipment. This requires evacuation of the system and accurate charging of refrigerant.
Timely contacting a service center will extend the life of your refrigerator and avoid food spoilage. Remember that even high-quality equipment, such as Liebherr or Siemensrequires care and timely repairs.
Why does the refrigerator click immediately after defrosting?
After defrosting, all parts of the refrigerator have the same temperature. When turned on for the first time, a sharp and uneven cooling of the plastic and metal occurs, which causes intense thermal expansion and louder than usual clicks. This is normal and will go away after a few hours of operation.
Can a new refrigerator click?
Yes, new refrigerators may click more often. This is due to the fact that the parts have not yet been ground in, and the lubricant in the compressor has not yet been distributed evenly. In addition, modern models often have thinner walls, which resonate more strongly.
Is it dangerous if the relay clicks but does not start the compressor?
Yes, it is dangerous. In this mode, voltage is applied to the starting winding, but the engine does not start. The current in the winding increases, which can lead to its burnout or insulation fire within a short time. Disconnection from the network is required.
Does the voltage level in the network affect clicks?
Yes, with low voltage in the network, the starting relay may not work correctly, making frequent clicks when trying to start. If your light often fluctuates, it is recommended to use a voltage stabilizer to protect your equipment.