Refrigerator knocks after defrosting - what to do and when to sound the alarm?

You defrost the refrigerator, turn it back on, and suddenly you hear a rhythmic tapping that hasn't happened before. The sound can resemble the ticking of a clock, light strokes, or even a metal knock. First thought: "Broken!" Don’t panic: 80% of the time technique-reaction Changes in temperature or humidity. However, you can not ignore the noise either - sometimes they signal serious malfunctions that will lead to a compressor breakage or a leak of Freon.

In this article, we will discuss all possible causes of tapping From harmless to critical, we will learn to distinguish working sounds from emergency ones, and give step-by-step instructions on what to do in each situation. We will pay special attention to models with the system. No Frost (e.g., Samsung RB37A5200SA, LG GA-B489YVQZ), where post-defrosting noises are most common. You will also find a table with a decoding of sounds by their nature and frequency – this will help to quickly diagnose the problem.

If your refrigerator is not just knocking, thunder, vibrate or make a grin This is another level of problems that requires a separate analysis. This is exactly what we're talking about. rhythmic tapping, appearing immediately or several hours after switching on.

1. Normal sounds: When knocking is not dangerous

Modern refrigerators (especially with the No Frost) are complex systems with many moving and heating parts. After defrosting, the technique undergoes several stabilization stages, each of which can be accompanied by extraneous sounds. Here's what's considered normal:

• 🔄 Thermostat (thermostat): when the refrigerator is turned on after defrosting, a relay is triggered, which closes / opens the contacts. This is accompanied by a click or a slight knock. In models Indesit and Atlant The sound may be louder due to the design of the relay.
• ❄️ Ice on the evaporatorIf the defrosting was incomplete, the remaining ice crystals can crack and fall when heated, creating knocking sounds. Especially noticeable in refrigerators. Bosch KGN39VL35R system LowFrost.
• 🔥 Compressor heating: metal parts when expanding from heat can slightly tap on the body. This is a temporary phenomenon (up to 30 minutes after switching on).
• 💧 Condensation in the drainage system: water flowing down the tubes sometimes creates gurgling or knocking sounds (typical for models) Liebherr CN 4015).

How to distinguish a normal knock from a malfunction? Take a simple test:

Estimate the frequency of the sound – if it repeats at intervals of 10-30 seconds, it is more of a thermostat.

Listen to if the intensity changes - working sounds usually subside after 1-2 hours

Check if the knock is accompanied by vibration of the body or heating of the side walls

Make sure the sound doesn’t get louder with time.

If all points are completed, and the knocking has not disappeared after 3-4 hours, proceed to the next section. Perhaps the problem lies deeper.

2. Common malfunctions that cause knocking

If tapping does not pass or are accompanied by other symptoms (poor cooling, constant operation of the compressor), it is a breakdown. Here. Top 5 Reasons Top Top 5 ReasonsThe refrigerator is knocking after defrosting:

Reason.	Nature of sound	Additional symptoms	Cost of repair (rubles)
Wear of compressor	Loud tapping at launch, vibration	It takes a long time to get a temperature, often turns off.	5 000–12 000
Fan breakdown No Frost	Cyclical knocking or grinding	Freezer's not working, put ice on the back wall.	2 500–6 000
Weakening of compressor anchorages	Metal knocking at work, rattling	Vibration of the body, displacement of the refrigerator	1 500–3 000
Drainage system clog	Gurgling or thumping	Water under vegetable drawers, unpleasant smell	1 000–2 500
Failure of the starting relay	Frequent clicks with pauses of 5-10 seconds	The compressor does not start or works in jerks	1 800–4 000

Refrigerators are particularly vulnerable inverter-compressors (e.g., Samsung RB30J3000WW or Hitachi R-B490PUC6X). Their motors are sensitive to voltage drops, and after defrosting can emit uncharacteristic sounds due to a malfunction in the electronic unit. If your model is in this category, First, check the voltage in the network. - it should be within 220V ± 10%.

Normal (linear)

Inverter

I don't know.

The other--

3. Diagnosis by the nature of the knock: decoding of sounds

To determine the cause more accurately, listen to intonation, frequency and source sound. We have collected audio portraits of the most common knocks:

• 🔨 Metal knocking at launch (1-2 strokes): most likely, it is trigger-relay. In models Atlant MXM 2835-90 It's located next to the compressor and can knock on the body when it's triggered.
• ⏱️ Rhythmic ticking (every 10-20 seconds):work thermostat or timer. Norm for refrigerators with No Frost.
• 🌀 Cyclical knocking with pauses (30 seconds of work – 2 minutes of silence): malfunction fan. Frequently found in LG GA-B429SLGL after 5 years of operation.
• 💥 Loud single impact when stopping the compressor: weakened shock absorbers Or the mounts are worn out.

To clarify the diagnosis, use this algorithm:

1. Turn off the refrigerator for 5 minutes, then turn it on again. If the knocking came immediately, the problem is trigger-relay or compressor.
2. Put your hand on the back wall below. If you feel vibration, check it out. compressor-holding.
3. Open the freezer and listen. Knocking from inside? The culprit-- fan or evaporator.

4. Step by step: what to do if the knocking does not pass

If you are convinced that knocking is not a normal sound of work, act according to this scheme:

Step 1: Checking the compressor anchorages

Weakened bolts are the most common cause of metal knocking. How to fix it:

1. Turn the refrigerator off the grid.
2. Move it away from the wall to access the back panel.
3. Find the compressor (black cylindrical block at the bottom).
4. Check all the bolts and nuts of the mount. They should be tightened. tightly but without clamping (Precise time is 1.5-2 Nm).
5. If the shock absorbers (rubber pads) are cracked, replace them.

Step 2: Cleaning the fan No Frost

In the refrigerator with the system No Frost (e.g., Beko GNE 114620 X) the fan may knock because of ice or foreign objects. Action:

1. Shut down the power.
2. Remove the back panel of the freezer (usually mounted on latches or screws).
3. Check the fan blades for ice or debris. Remove obstacles plastic-shoulder (not metal!)
4. Scroll the fan with your hand - it should rotate silently.

What to do if the fan blades are damaged?

If there are cracks or chips on the blades, the fan must be replaced. Do not try to repair it with glue – this will lead to imbalance and increased vibration. For models Samsung and LG original fans cost 1,500–3,000 rubles, for Indesit and Atlant — 800–1 500 ₽.

Step 3: Diagnostics of the trigger relay

If the refrigerator is knocking and non-start (or starts on the third or fifth attempt) is the fault of the relay. How to check:

1. Remove the relay from the compressor (usually it is fixed with a clip or screw).
2. Shake it - if you hear a knock inside, it's a sign contact-burn.
3. Call the contacts with a multimeter (the resistance between the terminals should be 20-50 Ohms).

Relays are not repairable - only replacement. For refrigerators. Biryusa and Stinol Universal models will be suitable Danfoss 103N0210 or Embraco ER3100.

5. Prevention: How to avoid knocking after defrosting

To prevent the refrigerator from knocking after defrosting, follow these rules:

• ⏳ Complete defrostingDo not turn on the refrigerator until all the ice has melted (including in drainage tubes). In the models with No Frost 12 hours is enough, in normal - up to 24 hours.
• 🔌 Stable voltage:use stabilizer or filterIf there are frequent horse racing on your network. The critical voltage for refrigerators is below 190V or above 240V.
• 🧊 Proper bootingDo not place heavy products (such as pickle cans) on top shelves – this shifts the center of gravity and increases vibration.
• 🧹 Cleaning the condenser: Dust on the rear grille impairs heat transfer, causing the compressor to work to its limit. Clean her up. vacuum-brush once every 6 months.

For refrigerators with No Frost mandatory annual preventive cleaning of the fan. In models Samsung and LG For this purpose, a special hatch is provided in the back wall of the freezer. In the fridge. Bosch and Siemens It may be necessary to remove the internal panel.

Once a month

Every 3-6 months

Once a year.

Only when the ice comes in.

I never defrost--

6. When to call the master: critical symptoms

Some situations require professional intervention. Contact the service center immediately., if:

⚠️ Attention.The refrigerator is knocking and cooling (temperature in the chambers above +10°C). It's a sign. freon leakage or compressor breakdown. Self-repair is not possible here – it is required. vacuuming and refrigerant refill.

• 🔥 Knocking is accompanied overheating (walls hot to the touch).
• ⚡ When you're on the network, you can hear it. cotton And the fridge knocks out the machine.
• ❄️ In the freezer. It forms a fur coat. thickness of more than 5 mm per day.
• 💦 Appears under the fridge oil (sign of compressor failure).

The cost of diagnosis in service centers is from 1,000 to 2,500 rubles. If the refrigerator is guaranteed, Don't open it yourself. This will cancel the guarantee obligations. For models Liebherr, Miele and Gorenje The compressor warranty is up to 10 years, but only under the condition of professional maintenance.

7. Frequent mistakes in eliminating knocking

When trying to get rid of tapping, users often take actions that only exacerbate the problem. That's what don't:

• 🔧 Tighten compressor attachments "by eye": pulled bolts can warp the frame or damage the tubes with freon. Use it. dynamometer.
• ❄️ Breaking off ice with a knife or fork: This leads to microcracks in the evaporator and subsequent leakage of Freon. Use it to speed up defrosting. dryer (hold at a distance of 30 cm).
• 🔌 Connect the refrigerator through the extension cord: This creates additional resistance and can cause the trigger relay to overheat. Always use. plug-in.
• 🧲 Use magnets to "eliminate vibration": This is a temporary solution that masks the problem (e.g., weakened mounts) and leads to more serious breakdowns.

It is especially dangerous to ignore the knocking in the refrigerator. linear-compressor (e.g., Whirlpool ART 9810). These models are sensitive to mechanical stress, and vibration can cause the winding-off In this case, the cost of repair will be 70-80% of the cost of a new refrigerator.

FAQ: Answers to Frequent Questions

Can I use a refrigerator if it knocks but freezes normally?

Yes, if the knocking appears only in the first hours after switching on and is not accompanied by other symptoms (overheating, vibration, poor cooling). However, We recommend watching the refrigerator for 2-3 days.. If the sound does not disappear or amplify - call the wizard to diagnose the starter relay or shock absorbers of the compressor.

Why does the knocking only appear at night?

This is due to two factors:

1. Voltage drop in the network (Many appliances are turned off at night and the refrigerator is powered unstable.)
2. Increased compressor load due to the lack of opening of the doors (the temperature in the chamber drops below the set, and the engine is running at full power).

Solution: Connect the refrigerator through voltage stabilizer and check the thermostat settings (optimum temperature: +4°C in the refrigeration chamber, -18°C in the freezer).

A new refrigerator knocks after the first defrosting - is it marriage?

Not necessarily. In the first 1-2 weeks of operation, new refrigerators (especially with the new ones) No Frost) may emit extraneous sounds due to:

• Laundry of compressor parts.
• Adaptations of the system No Frost to operating conditions.
• Freon pressure alignment in the system.

If the knocking has not disappeared after 2 weeks, contact the service center for verification. compressor-holding and launcher (These are frequent build defects).

How to reduce the knock of a refrigerator standing on an uneven floor?

Vibration and knocking due to uneven surface are eliminated as follows:

1. Adjust. front-legs Refrigerator level (use building level)
2. Put it under your hind legs. rubber-stick 2-3 mm thick.
3. If the floor is very uneven - set the refrigerator on rubber-mat (e.g., Anti-Vibration Mat).

Do not use wooden bars or books – they do not extinguish the vibration, but only shift the center of gravity.

The fridge is knocking. Atlant After the defrosting – what to check first?

In the fridge. Atlant (e.g., MXM 1705-80) most commonly knocking is associated with:

1. Weakening of compressor anchorages (The bolts are spinning due to vibration).
2. Breakdown of the launch relay (in models until 2018 of release used relays) RTK-XProne to burning contacts.
3. A drainage pipe clog. (Leads to gurgling and thumping).

Start by checking the compressor mounts – this is the most common problem. If the bolts are tightened, and the knock remains - replace the relay with Danfoss 103N0210 (Similar for most models) Atlant).