Sudden loud sounds emanating from household appliances can frighten any owner. The situation when the refrigerator seems to be shootingoften causes panic and is associated with serious damage or even an explosion. However, in most cases, these sharp clicks, crackles or pops do not pose a critical threat to the unit.
The acoustic background of a working compressor, the circulation of refrigerant and the thermal expansion of materials - all this creates a complex sound picture. It is important to learn to distinguish the normal sounds of mechanisms from the signs emergency condition. Understanding the physics of processes will help you keep calm and avoid unnecessary expenses on calling a technician.
In this article we will analyze in detail the mechanics of the occurrence of extraneous noise. We will look at the design of the starting relay, the features of deformation of plastic and metal parts when temperature changes. Issues related to improper installation and wear of internal components will also be raised.
The physics of thermal expansion: why the case cracks
The most common reason why a refrigerator makes sounds reminiscent of gunshots or the cracking of branches in a fire is banal thermal expansion. The interior of refrigerators and freezers is made of plastic or enamel, and the outer walls are often metal. With a sudden change in temperature, for example, after turning on the compressor or turning off the system No Frost, materials change their volume.
Plastic compresses and expands faster than metal. When different materials are connected to each other or have points of contact with different fastening rigidities, microscopic movements occur. These movements are accompanied by a sharp release of accumulated tension, which we hear as a loud click. This is especially often observed in new models or after defrosting.
The intensity of such sounds directly depends on the temperature difference. If you have just loaded warm food into the chamber or, conversely, have kept the door open for a long time in a hot room, the temperature contrast will be maximum. In this case, casing cracking can be very loud and frightening, but it is absolutely safe for equipment.
It is worth noting that older refrigerators, which used thicker sheets of metal and simple insulating materials, could click less frequently, but louder. Modern models with thin walls and complex multi-layer insulation are susceptible to this effect to a greater extent due to the heterogeneity of the composites used.
⚠️ Attention: If the cracking sound is accompanied by the appearance of an unpleasant burning odor or visible smoke, immediately unplug the device. This may indicate melting wiring or insulation, which is a sign of a short circuit.
Operation of the start relay and compressor
The heart of any refrigerator is the compressor, and its start is controlled by the start relay. It is this node that often becomes the source of characteristic clicks. When the motor is turned on, the relay sends an impulse to the starting winding to spin the shaft. This process is accompanied by a distinct electrical click that is heard throughout the room.
If the refrigerator clicks and does not turn onis making a series of quick knocks, this is an alarming symptom. This pattern indicates that the start relay is trying to start the engine, but is unable to do so. After a few seconds, the thermal protection is triggered, opening the circuit with a characteristic sound, and the cycle repeats. This may be caused by jamming of the compressor or failure of the relay itself.
In good condition, the click of the relay should be single and precede the start of a smooth hum of the motor. Modern inverter compressors are quieter and smoother, so any harsh sounds are more noticeable. However, even in them, mechanical valves can make sounds when the refrigerant pressure changes.
The frequency of the relay clicks in normal mode depends on the thermostat settings. The more often you need to maintain a low temperature, the more often you will hear the switching sounds. If the intervals between clicks become too short (less than 5-7 minutes of operation), it is worth checking the tightness of the door or the amount of loaded products.
How to check the relay yourself?
Unplug the refrigerator, remove the back cover and carefully remove the relay from the compressor. Shake it: if you can hear the internal parts clinking (like breaking glass), the relay is faulty and needs to be replaced.
Refrigerant circulation and gurgling sounds
Another source of noise, which users sometimes mistake for gunshots or crackling sounds, is the movement of freon through the system tubes. The refrigerant circulates in two states: liquid and gaseous. Flowing from the condenser to the evaporator through the capillary tube, it changes pressure, which may be accompanied by sounds similar to bursting bubbles or quiet pops.
These sounds are especially pronounced immediately after the compressor stops. The pressure in the system is equalized, and the remaining liquid freon can suddenly boil in the tubes, creating an acoustic effect. Systems No Frost add noise from fans, which may hum or crackle if an ice crust has formed on the blades.
If the sound resembles water pouring or loud gurgling, this is usually normal. However, if a whistling sound is added to this, this may indicate a freon leak. At the site of the microcrack, gas escapes under pressure, creating a characteristic whistling sound, which is sometimes masked under the general noise of the unit.
It is important to listen to the nature of the sound. Uniform flow of liquid is the normal operating mode of the refrigeration machine. Sharp, impact sounds in the tubes may indicate water hammer if moisture or oil has entered the system, which requires specialist intervention.
Problems with defrosting in No Frost systems
Owners of refrigerators with an automatic defrosting system often encounter loud sounds during the defrosting period. The heating element heats the evaporator, and the ice that has accumulated during the operating cycle begins to melt. Large layers of ice may fall off the evaporator fins with a loud crack that echoes throughout the housing.
In addition, water flowing into the drain pan may drip onto the hot heating element or metal surfaces, creating hissing and short ringing clicks. It's like a drop of water falling onto a hot frying pan. In some models, the defrosting sound can be quite loud, especially at night, when the apartment is quiet.
If an ice plug has formed in the drainage channel, water can freeze in unintended places, and then, when heated, expand sharply, creating stress in the plastic parts of the air ducts. This also results in a series of clicks. Regular defrosting (at least once a year) helps prevent the formation of excessive ice.
The defrosting system is controlled by a timer or an electronic module. If the clicking sounds become too frequent or last too long, the defrost sensor may be faulty. It can “stick”, forcing the heating element to work longer than necessary, which leads to overheating of the plastic elements and their deformation.
Fault diagnosis: table of symptoms
To understand whether your refrigerator requires repair or whether sounds are normal, you need to analyze the accompanying symptoms. Below is a table that will help classify the problem based on acoustic symptoms and the behavior of the equipment.
Pay attention to the frequency of repetition of sounds and the conditions under which they occur. A single bang when turning on the light or starting the engine is one thing, but a series of shots every 10 minutes is completely different.
| Sound type | Probable cause | Danger | Actions |
|---|---|---|---|
| Single loud click at start | Start relay actuation | No (Normal) | Observation |
| Series of clicks, the motor does not start | Relay or compressor malfunction | High | Call a technician |
| Crackling sound similar to burning wood | Thermal expansion of plastic/metal | No (Normal) | No action |
| Loud bang inside the chamber | Ice chipping or dishes bursting | Medium | Check products |
| Whistling or hissing | Freon leakage | High | Disconnect and repair |
This table is for reference only. Refrigerator models from different manufacturers (for example Indesit, Bosch, LG) may have their own design features that affect the sound background. Always check the instructions for your specific model.
⚠️ Attention: The design of the drainage system and the location of the heating elements may vary depending on the year of manufacture of the model. If you are not sure about the structure of your refrigerator, do not try to disassemble the defrost system yourself.
External factors and correct installation
Sometimes the cause of strange sounds lies not inside the unit, but outside. Incorrect installation is a common culprit for resonance. If the refrigerator is not level, vibrations from the operating compressor are transmitted to the housing and intensified. This can cause rattling of shelves, dishes and even the refrigerator frame itself, which adds up to a “shooting” effect.
Check the installation level using a building level. Height adjustment is made using the front legs. It is also important to make sure that the refrigerator does not touch the wall, cabinets or other furniture. The gap should be at least 5-10 cm on all sides for normal air circulation.
Another external factor is the condition of the electrical network. Power surges or poor connections in an outlet can cause sparking, which can be heard as a cracking sound. Check the plug and socket: they should not get hot or emit odors. Using a surge protector can protect equipment from unstable current.
The dishes inside can also be a source of noise. Glass bottles or jars touching each other when vibrating produce a ringing sound that may sound like gunshots. Make sure that the shelves are loaded evenly and that the products do not touch the back wall of the chamber where the cooling channels are located.
☑️ Checking the installation of the refrigerator
When an urgent call to the technician is necessary
Despite the fact that many sounds are safe, there are situations when delay can lead to complete breakdown of expensive equipment. If you hear a series of clicks, followed by silence, and the refrigerator stops freezing, this is a sign that the compressor does not start..
Long-term operation in the mode of constant attempts to start (click-pause-click) leads to burnout of the motor windings and failure of the start relay. In the worst case, the compressor itself may burn out, replacing which is often not economically feasible. Therefore, at the first signs of an incorrect start-up, it is better to contact a specialist.
The smell of burnt wiring or plastic is also a cause for concern. This may indicate overheating of the contacts in the electrical circuit or melting of the insulation. In this case, operation of the device must be stopped immediately until the malfunction is eliminated.
Do not ignore changes in the nature of the sound if they occur suddenly. If the refrigerator worked quietly for years, and suddenly began to “shoot” and hum loudly, it means that there was a malfunction in its operation. Early diagnosis allows you to eliminate the problem at the stage of replacing a small part, avoiding major repairs.
Frequently asked questions (FAQ)
Why does the refrigerator click loudly? at night?
At night there is silence in the apartment, so any sounds become more noticeable. In addition, the room temperature is lower at night, which can increase the contrast between the temperature inside and outside the chamber, increasing the effect of thermal expansion of materials. Also, at night, a defrosting cycle on a timer occurs more often.
Is it dangerous if the refrigerator cracks when you first turn it on?
No, when you turn it on for the first time or after a long defrosting, the cracking of plastic and metal due to sudden cooling is an absolutely normal phenomenon. It will go away on its own after a few hours of operation, when the temperature stabilizes.
Could the sound of a shot be due to a jar bursting?
Yes, glass containers can burst due to temperature changes or internal pressure of the products. The sound of breaking glass in the confined space of a cell can be very loud and harsh. Be sure to check the shelves and bottom of the chamber for fragments and food.
What to do if the clicks become more frequent after moving the refrigerator?
Most likely, the geometry of the installation is broken. Check whether the refrigerator is level and not tilted. Make sure that the legs fit tightly to the floor and that the unit itself does not wobble. Also check whether heating pipes or furniture are touching the vibrating housing.