A sudden hum or obsessive buzzing from kitchen appliances can unsettle any person. Refrigerators of the system No Frost are technically more complex than conventional models, so the range of possible sounds here is much wider. Understanding the nature of these sounds is the first step to saving the family’s nerves and budget.
Many owners begin to panic when they hear any extraneous knocking, but not all noises indicate a breakdown. Compressor, fans and the refrigerant makes specific sounds in normal operation. It is important to learn to distinguish the normal functioning of the unit from the signs of an impending disaster that requires the intervention of a specialist.
In this article we will analyze in detail the mechanics of the system No Frost and explain which nodes can become a source acoustic discomfort. You will learn when it is enough to simply move the equipment, and in which cases it will be necessary to replace expensive parts.
Sound physiology: how No Frost works
The system No Frost ("no frost") is fundamentally different from drip cooling technology. In such refrigerators, air circulates forcibly, constantly passing through an evaporator hidden behind the back wall of the chambers. It is this circulation that creates the main background to which the user gets used to.
The main source of sound is compressorwhich compresses the refrigerant. In modern inverter models, it operates almost silently, changing power smoothly. However, old or faulty motors may produce a loud hum, vibration or metallic clanging sound when starting up.
The second key element is fan. There can be one or two of them in the system (for the refrigerator and freezer compartments separately). The blades rotate at high speed, dispersing cold air. If ice builds up on the blades or dust gets into the bearing, a characteristic noise begins.
⚠️ Attention: If the noise volume increases sharply in the first days after purchase, this may not be a breakdown, but a feature of the installation. Make sure that the equipment is level and does not touch the walls.
The third source is movement refrigerant through the tubes. Gurgling, hissing or the sound of running water is a normal physical phenomenon. Freon passes from liquid to gaseous state and back, which is always accompanied by acoustic effects. In Atlant refrigerators or Indesit this sound can be heard more clearly due to the design of the pipelines.
Why do old refrigerators make more noise?
Over the years, the oil in the compressor thickens, and the tubes lose their original geometry due to vibrations. This leads to an increase in resonance and general hum, even if the technical components are working properly.
Natural sounds: when it’s too early to sound the alarm
Before looking for a repairman, it is necessary to carry out a primary investigation. diagnostics. There are a number of sounds that are absolutely normal for working equipment. Ignoring this fact leads to unnecessary service costs.
Users are often frightened by clicks. It works thermostat or a relay, turning the power circuit on and off. On electronically controlled models, the defrost sensor may click. The sound is usually short and loud.
Also considered normal:
- 🌊 Quiet gurgling and overflow of liquid inside the housing immediately after turning off the motor.
- 💨 The whistling sound of air escaping from the technological holes when closing the door.
- 🔨 Single impacts or crackling of plastic when the temperature changes (thermal expansion of materials).
Particular attention should be paid to sounds when defrosting. In the No Frost system, defrosting occurs automatically. Drops of melt water, flowing onto the hot heater of the heating element, can emit a hissing sound similar to a boiling kettle. This is the normal operating mode.
Mechanical reasons: vibration and installation
The most commonplace, but common cause of noise is incorrect installation. If the refrigerator is placed on an uneven floor or is skewed, the vibration from the running compressor is transmitted to the body and resonates. This creates a low-frequency hum that gets louder at night.
Check the adjustment feet. They should rest firmly on the floor. Sometimes it is enough to tighten them half a turn to eliminate the rattling. The distance to the walls is also important: the gap at the back should be at least 5-7 cm for free air circulation.
Another mechanical problem is the contact of internal elements. Vibration can cause:
- 🔌 The power cord or tubes touch the back wall of the case.
- 🥤 Bottles on the shelf shake and knock against each other.
- 🧊 The egg tray or containers do not sit tightly in their sockets.
If you notice that it is the compressorthat is making noise, check its mounting bolts. Over time they may weaken. In some models LG or Samsung there are rubber damper washers under the motor. If they dry out or fly off, metal will begin to beat on metal.
Problems with the fan: ice and wear
In systems No Frost the fan is the heart of circulation. If he starts making noise, you can't ignore it. Most often the problem lies in freezing. The defrosting system could fail, and a “fur coat” had grown on the blades.
The ice crust disrupts the balancing of the impeller. The fan begins to hum, vibrate and even touch the ice with its blades. This creates a nasty grinding noise. In this case, a full refrigerator is required (for at least 24 hours with the power turned off). Defrost The second reason is wear of the bearing or fan bushing. Symptoms: defrosting refrigerator (for at least 24 hours with the power turned off).
The second reason is wear of the fan bearing or bushing. Symptoms:
- 📉 A gradual increase in howling, turning into a hum.
- 🔄 The sound appears and disappears (depending on the operating cycle).
- ⛔ The fan may stop completely, which will lead to overheating of the motor.
Replacing the fan is not a complicated procedure, but it requires disassembling the rear panel in the freezer. It is important to choose an analogue with the same rotation characteristics and dimensions.
☑️ Fan diagnostics
Faults in the compressor and start relay
If the noise comes directly from the motor at the rear, the reasons may be be serious. Compressor is the most expensive unit. A loud metallic knock upon startup often indicates wear of the internal valves or piston group.
A frequent problem is a malfunction. start relay. This is a small box on the compressor housing. If it fails, the engine may hum but not start, or it may start with a loud clicking or crackling sound. In this case, the relay must be replaced, otherwise the motor winding will burn out.
Table of main compressor sounds:
| Sound type | Probable cause | Necessity repair |
|---|---|---|
| Smooth low hum | Normal operation | No |
| Loud clicking and buzzing | Relay malfunction or jamming | High |
| Metal clang | Destruction of the motor mount inside | Replacing the compressor |
| Whistling during operation | Freon leak or problem with the valve | Average |
It is important to note that in inverter models (for example, Bosch or Haier) the sound character is different from linear compressors. They can emit a high-frequency whistle or squeak, which is the norm for them when electronics operate.
⚠️ Attention: If the compressor is humming, but the refrigerator is not cooling, and after a few minutes it turns off, immediately unplug the appliance from the outlet. Further operation in this mode will lead to burnout of the winding.
Drainage system and foreign objects
Sometimes the source of noise is not technical components at all, but forgotten little things. The vibration of the refrigerator can move light objects standing nearby or on top. Check to see if a spoon has fallen behind the refrigerator or if dishes in a nearby cabinet are rattling.
It is also worth checking the drainage system. If the water drain tube is pressed against the body or pinched, the water flow may create a whistling sound. In systems No Frost water is discharged into a special tray above the compressor, where it evaporates. If the tray is misaligned, drops may drip loudly onto the hot metal.
Resonance of internal shelves is rare, but occurs. Glass shelves, if they are not tightly inserted into the guides, can vibrate in response to the motor. Try removing the shelves and turning on the refrigerator. If the noise disappears, the problem has been found.
Frequently asked questions (FAQ)
Why is the new refrigerator noisier? old?
Modern models often have more powerful compressors for quick freezing and compliance with eco-standards. In addition, the thin walls of modern cases insulate sound worse than the massive metal of old Soviet units.
Is it possible to lubricate a fan if it hums?
A temporary measure. You can drop a drop of machine oil into the bearing, but this will not solve the wear problem. It is better to order and install a new part, since the lubricant will quickly burn out or be washed away by condensation.
Is it normal for the refrigerator to crack at night?
Yes, silence at night makes sounds more noticeable. A cracking sound is often associated with automatic defrosting cycles or the expansion of plastic when temperature conditions change.
Does the refrigerator hum if there is little food in it?
An empty refrigerator works in a more ragged rhythm, turning on and off more often. The products work as a thermal accumulator. However, the noise level itself should not change dramatically.