The appearance of extraneous sounds in household appliances is always alarming, especially if it sounds like gunshots or loud clicks. When the refrigerator is firing, owners often panic, fearing an explosion or serious damage, but the nature of these sounds most often lies in the physical processes of expansion and contraction of materials. In most cases, sharp sounds resembling flakes or crackling indicate normal operation of the defrosting system or thermal deformation of the plastic.
However, these signals cannot be ignored, as they may indicate more serious problems with compressor or the electrical part of the unit. Understanding the difference between natural noise and signs of trouble can help you save money on calling a technician or, conversely, prevent catastrophic equipment failure. Next, we will analyze in detail the physics of the process, design features and diagnostic methods.
It is important to immediately note that the nature of the sound is crucial for correct diagnosis. The dull crack of plastic and the loud click of a relay are completely different phenomena that require different approaches. In this article, we will systematize knowledge about why such sounds occur and create an action algorithm for the owner.
Physics of the process: thermal expansion of materials
The most common reason why a refrigerator makes sounds similar to shots or crackling is banal thermal expansion. The inner walls of the chamber, shelves and evaporator are constantly subject to cyclic heating and cooling. The plastic from which the inner box is made and the metal of the evaporator have different coefficients of thermal expansion, which leads to microscopic movements and a characteristic sound.
When temperature the inside of the chamber changes sharply, for example, immediately after turning on the compressor or at the start of the defrosting cycle, the materials react instantly. Plastic contracts or expands faster than metal, creating stress at the attachment points. When the voltage reaches a critical point, a sharp breakdown occurs, which we hear as a loud click or even a pop.
⚠️ Attention: If the crackling sound occurs every few minutes and is accompanied by visible swelling of the chamber walls or the appearance of the smell of burnt plastic, immediately disconnect the device from the network. This may indicate overheating of the insulation or a short circuit.
Such sounds are especially often observed in new refrigerators or after prolonged defrosting. During this period, the materials have not yet “got used to” constant temperature changes. Over time, the frequency of such “shots” usually decreases, and they become less loud.
Why do old refrigerators crack louder?
In older models, plastic loses its elasticity due to the drying of plasticizers. It becomes more rigid and brittle, so the expansion and contraction processes take place with greater force and sharper sounds. In addition, in older units, the panel fastenings may have become loose, which increases the resonance.
Operation of the defrost and evaporator system
If your refrigerator is equipped with a No Frost or drip defrost system, then periodic clicks are an integral part of their operating cycle. During the defrosting process, the ice that has accumulated on the evaporator begins to melt, and the evaporator itself heats up. A sharp change in the temperature of the metal causes its expansion, which is accompanied by characteristic sounds.
In addition, in refrigerators with automatic defrosting, a timer or an electronic control module is responsible for this process. When switching modes (for example, switching from cooling to defrosting), mechanical switching of contacts or valves may occur, which can also be heard as a click. This is a normal situation that does not require intervention.
However, if the sounds become too frequent or loud, it is worth checking the condition of the defrost heater. If it does not work correctly, local overheating is possible, causing deformation of nearby parts. Also, the source of the sound can be flowing water: drops falling on the hot parts of the heater or in the drainage system can produce hissing or short pops of steam.
Problems with the starting relay and compressor
A more serious cause of clicking sounds is a malfunction in the electrical engine starting circuit. Start relay is a device that provides an impulse to start the compressor. If the relay is faulty or worn out, it may make loud, loud clicking noises as it tries to start the engine but fails to do so. In such cases, the compressor may hum, but not start, or start and immediately stall.
The situation when the refrigerator “shoots” in the area of the motor-compressor (usually the lower rear part of the unit) requires special attention. Clicking sounds may indicate that the contacts inside the relay are burnt and stuck, or that a spark is occurring. This is dangerous because it can lead to burnout of the motor windings or even fire.
- 🔊 A loud single click Before starting the motor, the relay is operating normally.
- 🔁 A series of frequent clicks without starting the compressor is a sign of a faulty starting device or low voltage in the network.
- 💥 Sound like a gunshot in the back - a possible breakdown of insulation or an explosion of condensation in the electrical part.
To diagnose this problem, you can carefully (observe safety precautions!) listen to the back of the operating refrigerator. If the clicks are synchronized with attempts to start the motor, most likely you will need to replace the starting relay or the compressor itself.
⚠️ Attention: Independent replacement of the starting relay is only possible if you have skills in working with electrical appliances. Be sure to disconnect the refrigerator from the mains before removing the compressor protective casing!
The influence of refrigerant and water hammer
One of the specific causes of sharp sounds is the movement of refrigerant through the piping system. Normally, freon circulates silently or with a quiet gurgle. However, if an air lock has formed in the system or a mixture of refrigerant phases has occurred, an effect resembling a shot or a strong blow may occur.
Also worth mentioning is a phenomenon known as hydraulic hammer. It can occur if liquid freon enters the compressor instead of gaseous freon. This often happens when the refrigerator is not charged correctly or when there are severe temperature disturbances. Liquid, unlike gas, is not compressed, and its sudden entry into the compression chamber causes a shock wave and a characteristic sound.
If you hear such sounds, this is an alarming signal. Water hammer can quickly damage a compressor because it is not designed to compress liquid. In such cases, it is often necessary not only to replace the compressor, but also to completely flush the system and replace the filter-drier.
Diagnostic table of sounds
To make it easier for you to navigate the variety of sounds that your unit can produce, we have compiled a summary table. It will help classify the problem by the nature of the sound and its localization.
| Sound type | Localization | Probable cause | Need for repair |
|---|---|---|---|
| Deaf crackling | Inside the chamber, walls | Thermal expansion of plastic | Not required |
| Audible click | Rear, below (motor) | Starter operation relay | Required if it does not start |
| Clap/Shot | Across the entire chamber | Evaporator deformation during defrost | Not required |
| Series of clicks | Control unit/relay | Electronics or relay malfunction | Urgent |
| Hissing with a pop | Drain/evaporator | Water contact with the heater | It is advisable to check the drainage |
Use this table as a primary diagnostic tool. Remember that an accurate diagnosis can only be made by a specialist using special equipment, especially if we are talking about a sealed circuit.
Instructions for self-testing
If you decide to carry out the initial diagnostics yourself, act consistently and carefully. Your task is to localize the source of the sound and determine its periodicity. Do not try to disassemble complex components without the appropriate knowledge.
Start with visual inspection and listening. Make sure that the refrigerator is level, the adjustment feet are adjusted, and that the cabinet is not touching walls or furniture, which could increase resonance. Then listen to the operation in different modes.
☑️ Algorithm for checking the refrigerator
- Disconnect the refrigerator from the mains for 15-20 minutes to reset possible electronic errors and allow temperature stabilize.
- Turn on the device and stand nearby, waiting for the first start of the compressor.
- Fix the moment of the click: is it before motor humming, during or after it stops.
- Check the temperature in the chambers: if the refrigerator does not freeze, but clicks, the problem is critical.
If during the check you find that the compressor is trying starts up, clicks, but does not start, and at the same time gets very hot - stop experiments immediately. Further switching on may lead to permanent engine failure.
⚠️ Attention: Models of refrigerators from different manufacturers (Indesit, Bosch, LG, Samsung) may have unique design features for sound insulation and fastening of components. What is normal for one model may be an anomaly for another. Always check the user manual.
Frequently asked questions (FAQ)
Why does the refrigerator click loudly at night?
At night, the overall noise level in the apartment decreases, and the sounds of operating equipment become more noticeable. In addition, the power supply often drops at night, which can make it difficult for the compressor to start, causing the start relay to click more often. Also at night, the refrigerator doors are opened more often (dinner, drinks), which provokes more frequent power cycles.
Is it dangerous if the refrigerator makes one loud bang?
A single loud bang is most often the result of a sharp thermal expansion of plastic or metal (evaporator). If after this the refrigerator continues to freeze normally and does not emit a burning smell, most likely there is no danger. However, it is worth observing the device in the coming hours.
Can a new refrigerator shoot?
Yes, new refrigerators can make more pronounced sounds during the first cycles of operation. This is due to the fact that the materials have not yet gone through the cycles of “shrinkage” and expansion. Also, in new models with inverter compressors, the sounds may be quieter, but more high-frequency, which is sometimes perceived differently.
What to do if the clicks become more frequent after defrosting?
After defrosting, excess moisture may remain in the system, which, when evaporated, creates sounds. Also, a sharp temperature change could cause increased expansion of materials. Let the refrigerator run idle for several hours. If the clicking does not stop and is accompanied by other symptoms, contact the service department.
Is crackling a sign of a freon leak?
The freon leak itself is usually silent. However, if a leak introduces air or moisture into the system, it can change the refrigerant circulation pattern and cause strange sounds. But more often, the crackling sound is not directly related to the amount of freon, but is a mechanical or electrical effect.