Have you noticed that the refrigerator has started making strange knocking sounds? This is not always a reason to panic - some noise is considered normal, especially in new models with system No Frost or inverter compressors. However, if the knocking is repeated rhythmically, accompanied by vibration or a change in temperature in the chambers, this may indicate a malfunction.
In this article we will analyze all possible causes of knocking in the refrigerator - from harmless (for example, pipes touching the body) to serious (breakage of the compressor or fan). You will learn how to diagnose the problem yourself, when you can get by with simple adjustments, and when you need to call a technician. We will also provide a checklist for checking the refrigerator and answers to frequently asked questions on this topic.
1. Normal refrigerator noises: when not to worry
Modern refrigerators are complex devices with several moving parts. Many sounds that seem suspicious are actually normal. For example:
- 🔄 Relay clicks when turning the compressor on/off (usually every 10–20 minutes). This is normal operation of the thermostat.
- 💨 Fan noise in models with No Frost - may resemble a slight crackling or whistling.
- 🌡️ Crackling of plastic when the temperature changes (the body is slightly deformed). More often heard in new refrigerators.
- 💧 Gurgling or overflowing - circulation of refrigerant through the tubes.
If the sounds are quiet, irregular and not accompanied by other symptoms (for example, the refrigerator is not freezing or overheats), most likely, everything is in order with the equipment. Pay attention to noise intensity: at night it may seem louder due to the silence in the room.
2. The compressor is knocking: causes and solutions
The compressor is the “heart” of the refrigerator, and its malfunctions often manifest themselves through knocking. Let's consider the most common cases:
| Symptom | Possible cause | Solution |
|---|---|---|
| Rhythmic knocking during operation, body vibration | The compressor is loose or touching tubes | Tighten the bolts or put in rubber gaskets |
| Loud knocking at start-up, then silence | The starting relay does not work, the compressor “sticks” | Replace the relay or compressor (required master) |
| Knock + refrigerator does not freeze | Compressor piston jammed | Only compressor replacement |
| Knock when turning off the compressor | Hydraulic shock in the system (excess refrigerant). In this case, the part must be replaced. To check, you can use a multimeter: the resistance of the capacitor must be within the limits indicated on its body. | Diagnostics and refilling with freon |
If the compressor is knocking only when starting, the problem may be starting capacitor — it loses capacity over time and does not provide the required current. In this case, the part must be replaced. You can use a multimeter to check: the resistance of the capacitor must be within the limits indicated on its body.
⚠️ Attention: Do not try to disassemble the compressor yourself - there is freon inside under high pressure. If the tubes are damaged, a gas leak may occur, which is hazardous to health.
☑️ Compressor diagnostics
3. Problems with the fan: why it knocks and how to fix
In refrigerators with a system No Frost the knock is often associated with the fan that blows on the evaporator. The main reasons:
- ❄️ Ice on the blades — if the fan touches ice, it starts knocking when rotating. This occurs due to a malfunction of the defrost system.
- 🔧 Loose fastening —the fan can hang on the motor shaft.
- 🐭 Foreign objects —pieces of food, packaging or even insects sometimes get into ventilation holes.
- 🔄 Bearing wear —over time they become loose, and the fan begins to hit the housing.
To check the fan, unplug the refrigerator and wait until it is completely defrosted (if there is ice). Then open the back panel in the freezer (in most models it can be easily removed) and try turning the blades by hand. If they rotate with difficulty or a grinding sound is heard, the problem is in the bearings. Samsung, LG And Indesit it comes off easily) and try turning the blades by hand. If they rotate with difficulty or a grinding noise is heard, the problem is in the bearings.
How to remove the fan in a No Frost refrigerator
Unplug the refrigerator and defrost it. Remove the back panel of the freezer (usually secured with latches or screws). Disconnect the fan power connector. Unscrew the mounting screws and carefully remove the fan. Clean the blades from ice and dirt.
If the fan knocks due to ice, check defrost heater (heating element) and defroster (defrost sensor). In 80% of cases, the problem is solved by replacing the heating element - this is an inexpensive part, and you can install it yourself.
4. Knocking from tubes and condenser: how to eliminate vibration
Sometimes knocking occurs not because of a breakdown, but because of touching of the tubes on the body or about each other. This is especially noticeable in refrigerators with an open back wall (for example Atlant or Biryusa). Reasons:
- 🔨 Incorrect installation —the refrigerator is not level and the tubes sag.
- 🔥 Overheating of the condenser — under high load, the tubes expand and can touch the walls.
- 📦 Transportation —after transportation, the fastenings of the tubes could become loose.
To eliminate knock:
- Unplug the refrigerator and move it away from the wall.
- Inspect the back wall - find the tubes that touch the body.
- Carefully bend them or place pieces of foam rubber/rubber under them.
- Check that the refrigerator is level (use a level).
⚠️ Attention: Do not use metal objects to fix the tubes - they can damage copper or aluminum parts. It is better to take a soft material, for example, polyethylene foam.
If knocking appears only when the first turn on after defrosting, this may be due to hydraulic shock in the system. In this case, it will help blowing the capillary tube, but this procedure must be performed by a master.
5. Knocking due to a faulty thermostat or relay
The thermostat and start-up relay are responsible for turning the compressor on/off. If they do not work correctly, this can result in rhythmic knockingclicking or even rattling. Signs of malfunction:
- 🔁 The compressor turns on too often (every 1-2 minutes).
- ❌ The refrigerator does not turn off at all.
- ⚡ When turned on, a loud click is heard, but the compressor does not start.
- 🌡️ The temperature in the chambers does not correspond to the set temperature.
To diagnose the thermostat:
- Disconnect the refrigerator from network.
- Remove the protective casing from the thermostat (usually it is located next to the temperature control knob).
- Test the contacts with a multimeter in resistance test mode. At room temperature, there should be zero resistance between contacts 3 and 4. If there is no resistance, the thermostat is faulty and requires replacement. The start-up relay is checked in the same way, but it is more difficult to diagnose without experience. If you hear a sound when you turn on the refrigerator, but the compressor does not start, most likely the relay is “stuck” and needs to be replaced. The cost of a new part is from 500 to 2000 rubles, depending on the model. zero resistance.
- If there is no resistance, the thermostat is faulty and requires replacement.
The start-up relay is checked in a similar way, but it is more difficult to diagnose without experience. If you hear when you turn on the refrigerator loud click, and the compressor does not start, most likely the relay is “stuck” and needs to be replaced. The cost of a new part is from 500 to 2000 rubles, depending on the model.
6. Knocking due to breakdown of other components: what else can make noise
Rarely, knocking in the refrigerator is associated with other elements. Let's consider less obvious reasons:
| Unit | Knock pattern | How to check |
|---|---|---|
| Ice maker motor | Short clicks when typing ice | Turn off the water supply and check if the knocking noise disappears |
| Solenoid valve (in models with water) | Rhythmic tapping when opening the door | Listen if the sound changes when you press the dispenser water |
| Door closing sensor | Single click when opening/closing | Check whether the backlight works when the door is opened |
| Control unit transformer | Quiet humming with periodic clicks | The knock should disappear when the refrigerator is disconnected from the mains |
If the refrigerator is equipped with water dispenser or ice maker, check their operation. Sometimes knocking occurs due to incorrect installation of the water filter or clogged pipes. In this case, flushing the system or replacing the cartridge will help.
In refrigerators with electronic control (for example, Bosch or Liebherr) knocking can come from control unit relay. If the sound appears when the temperature changes on the display, the board may be faulty. In this case, diagnostics are required at a service center.
7. When to call a technician: signs of serious breakdowns
Some faults cannot be fixed on your own. Contact a specialist if:
- 🔧 The knock is accompanied by a freon leak (the refrigerator is not freezing, there are oil stains on the back wall).
- ⚡ Compressor does not turn on at all, the thermostat is working.
- 🌡️ The temperature in the chambers rises above +10°C, despite the motor running.
- 💥 Heard popping or explosions (the compressor winding may be damaged).
- 🔥 Refrigerator body gets very hot in one place (risk of fire).
The cost of repairs depends on the breakdown:
- Replacement of the starting relay - from 1,500 rubles.
- Compressor repair - from 5000 rubles. (plus the cost of freon).
- Fan replacement - from 2500 rubles.
- Elimination of freon leaks - from 4000 rub.
⚠️ Attention: If the refrigerator is under warranty, do not disassemble it yourself! Doing so may void your warranty. Contact an authorized service center.
Frequent questions about knocking in the refrigerator
Why does the new refrigerator knock louder than the old one?
Modern models are equipped with inverter compressors that operate at variable speeds. This may create additional vibrations, especially if the refrigerator is placed on an uneven surface. Also, new refrigerators often use more powerful system fans No Frostwhich may make more noise.
To reduce noise, check:
- Is the refrigerator installed level (use a level).
- Are the tubes touching the back wall.
- Are there any foreign objects near the ventilation holes.
Is it possible to replace the compressor yourself?
Theoretically yes, but in practice this is a difficult task that requires special equipment:
- A vacuum pump for pumping out freon.
- Cylinder with new refrigerant (the type of freon depends on the model).
- Turns for soldering copper tubes.
- Gauge manifold for refilling.
Great without experience risk overfilling or underfilling of freon, which will lead to repeated breakdown. In addition, when soldering tubes, you can damage the insulation or cause a leak. If you are not confident in your skills, it is better to entrust the replacement of the compressor to a professional.
The refrigerator is knocking Indesit —what to do?
In refrigerators Indesit (especially models Indesit DF 4180, Indesit TS 167), knocking is often associated with:
- Loosening the compressor fastenings —tighten the bolts or place rubber gaskets.
- Fan malfunction —in models with No Frost check that it hasn't hit Is there ice on the blades.
- Thermostat breakdown —if the knocking is accompanied by constant operation of the compressor.
Also in Indesit a problem that often occurs s with a capacitor (it may rattle when starting). You can replace it yourself - the part costs about 300–500 rubles.
How to reduce the noise of the refrigerator at night?
If knocking interferes with sleep, try the following methods:
- 📍 Rearrange the refrigerator away from the bedroom (for example, in the kitchen or into the corridor).
- 🔧 Adjust the legs —they should fit snugly to the floor.
- 🛠️ Install anti-vibration gaskets under the compressor (sold in spare parts stores).
- ⏱️ Set up the “Night mode” tariff (if included in your model) - the refrigerator will operate more quietly in the dark.
If all else fails, check freezing mode. Perhaps the refrigerator is operating at maximum power - reduce the temperature by 1-2 degrees.
Is the refrigerator knocking after defrosting - is this normal?
After defrosting, knocking can appear for two reasons:
- Condensation in the system - when turned on freon begins to circulate, and if there is moisture left in the tubes, gurgling or knocking sounds are heard. This is normal and should go away within 1–2 hours.
- Hydraulic hammer —if the refrigerator is turned on immediately after defrosting, the freon may not have time to distribute evenly throughout the system. In this case, the knocking will be loud and rhythmic. Solution: turn off the refrigerator for 30 minutes, then turn it on again.
If the knock does not go away for more than a day, check oil level in compressor - perhaps it has been redistributed after defrosting.