Have you ever Have you ever wondered how the refrigerator “understands” when it’s time to turn on the compressor and when it’s time to rest? Behind this magic there is a small but critical detail - bellows. Without it, your refrigerator would either turn into a freezer with Antarctic temperatures, or, conversely, would become a warm food cupboard. Even if you have never heard of a bellows, it works in your kitchen every day - and today we will figure out exactly how.
The bellows is not just “another tube” in the cooling system. This heat-sensitive element, which, paired with a thermostat, controls the climate inside the refrigerator and freezer compartments. Its breakdown can lead to a variety of problems: from a harmless increase in temperature to complete failure of the equipment. In this article we will tell you in detail where the bellows is located, how it works, what signs can be used to suspect its malfunction - and what to do if it really breaks down.
What is a bellows and what does it look like
A bellows in a refrigerator is corrugated metal tube, filled with a special refrigerant (usually freon or its analogues). It is part thermostatic circuit and is directly connected to the thermostat. The main feature of the bellows is its ability change length depending on temperature. When the refrigerator gets warmer, the tube extends and closes the contacts of the thermostat, starting the compressor. When cooling, the process goes in the opposite direction.
Externally, the bellows looks like a thin zigzag tube, usually made of copper or brass, with a diameter 2–4 mm. It can be:
- 🔹 Open —visible to the naked eye (more often in older models of refrigerators)
- 🔹 Hidden —hidden under the plastic housing of the thermostat (modern devices)
- 🔹 With a pigtail — with an additional capillary outlet for more accurate temperature measurement
In most household refrigerators (Atlant, Indesit, Samsung, LG), a bellows is attached to the evaporator or placed next to it in order to read the temperature as accurately as possible. In models with a system No Frost it is often installed with air ducts, and in drip refrigerators - directly on the back wall of the chamber.
The principle of operation of the bellows: physics in action
The operation of the bellows is based on two physical laws:
- Thermal expansion of gases. When heated, the refrigerant inside the tube increases in volume, stretching the corrugated walls.
- Elasticity of the metal. The bellows material (copper/brass) has “shape memory” and tends to return to its original state when cooled.
The operation cycle looks like this:
- The temperature in the refrigerator rises → the refrigerant in the bellows heats up and expands.
- The tube extends and, through a lever mechanism closes the contacts of the thermostat.
- The thermostat sends a signal to the start relay, which starts the compressor.
- The compressor pumps out heat from the chamber, the temperature drops → the refrigerant in the bellows is compressed.
- The bellows is shortened, the thermostat contacts open, the compressor stops.
It is interesting that in modern refrigerators with electronic control (for example, Bosch KAN92VI30R or Liebherr CNesf 4866) the bellows often works not directly, but through pressure sensor, which converts mechanical extension into an electrical signal. This allows you to more accurately control the temperature and save energy.
Where the bellows is located in the refrigerator: search by model
The location of the bellows depends on the type of refrigerator and its design. Here are typical installation locations:
| Refrigerator type | Bellows location | Examples of models |
|---|---|---|
| Drip (with a “crying” evaporator) | On the back wall of the refrigerator chambers, attached to the evaporator or built into the thermostat | Atlant MXM 1705-100, Biryusa 140 |
| No Frost (full or partial) | Inside the duct or next to the fan, often hidden by a plastic casing | Samsung RB-30 J3200SA, LG GA-B489 YDQZ |
| Two-chamber with mechanical control | In the freezer (for the freezer thermostat) and in the refrigerator (for the main thermostat) | Indesit DF 4180 W, Beko CNK 335120 |
| With an electronic display | The bellows is integrated into the control unit, can be replaced thermistor | Liebherr CBPesf 4043, Bosch KIN86AF30R |
To find the bellows in your refrigerator:
- Unplug the refrigerator and remove all food.
- Remove the plastic cover of the thermostat (usually located inside the chamber or on the top panel).
- Look for a thin one a corrugated tube going from the thermostat to the evaporator.
⚠️ Attention: In refrigerators with a system No Frost it is not recommended to remove the air ducts yourself to find the bellows - this may disrupt air circulation. Refer to the diagram in the instructions or call a specialist.
Signs of a bellows malfunction: when to sound the alarm
The bellows is a durable part, but not eternal. Over time, it may lose its seal, become deformed, or become clogged. Here 5 key symptomsthat something is wrong with him:
- ❄️ The refrigerator does not turn off. The compressor runs non-stop, but the temperature in the chamber does not drop below +10…+15°C. This means that the bellows does not compress does not open the thermostat contacts.
- 🔥 Excessive cooling. The food in the refrigerator compartment freezes and ice forms on the back wall. The culprit is the bellows, which when heated, does not start the compressor on time. Excessive cooling does not extend. The characteristic sounds of the thermostat operating are heard, but the motor does not turn on. Probably the bellows does not lengthen when heating and does not start the compressor on time.
- 🔊 Clicks without starting the compressor. The characteristic sounds of the thermostat operating are heard, but the motor does not turn on. Probably a bellows stuck is in one position.
- ⏱️ Uneven operating cycles. The compressor turns on too often or, conversely, “falls asleep” for a long time. This is a sign that the bellows responds to temperature with a delay.
- 💧 Refrigerant leak. If oily stains appear on the floor under the refrigerator, and the bellows has lost its seal, it will have to be replaced.
It is important to distinguish a bellows failure from a malfunction of the thermostat or compressor. For example, if the refrigerator does not turn on at all, the problem is most likely starting relay or electronics. But if the temperature “walks” from -5°C to +20°C in a few hours, the bellows is to blame.
How to distinguish a bellows failure from a thermostat malfunction?
If When you turn the thermostat knob, clicks are heard, but the compressor does not respond - the problem is in the thermostat. If there are no clicks at all, and the bellows is externally deformed, it is his fault.
How to check the bellows for functionality
You can check the bellows at home without special tools. You will need:
- 🔧 Screwdriver (for removing the thermostat cover)
- 🕯️ Hairdryer or container of hot water
- ❄️ Ice or frozen food
- 📏 Ruler or caliper (optional)
Step-by-step instructions:
Unplug the refrigerator and remove the food|
Remove the thermostat cover (usually attached to latches or screws)|
Carefully remove the bellows from the fastenings (do not bend the tube!)|
Immerse the tip of the bellows in hot water (50–60°C) and observe its elongation|
Cool the bellows with ice - it should contract to the original size|-->
Normal reaction of the bellows:
- 🔥 When heated to 40–50°C, the elongation should be 10–15 mm (depending on the model).
- ❄️ When cooled to 0°C, the tube returns to its original position.
- ⚡ When extended, a slight click should be heard (the thermostat contacts are activated).
⚠️ Attention: If the bellows does not respond to temperature or is deformed (bent, dented, with cracks), it must be replaced. Attempts to “straighten” the tube will lead to a refrigerant leak and final failure.
Causes of bellows failure and how to avoid them
The bellows rarely break, but it is still possible to prevent its wear. Here are the main causes of malfunctions:
| Cause of breakdown | Consequences | How to prevent |
|---|---|---|
| Mechanical damage (impacts, bends) | Cracks, refrigerant leakage, loss of tightness | Do not drop the thermostat when cleaning, do not put pressure on the tube |
| Metal corrosion | Thinning of walls, depressurization | Dry the refrigerator regularly, avoid condensation on contacts |
| Clogging of the capillary | Slow response to temperature, unstable operation | Do not allow dirt to get in during repairs, use clean tools |
| Natural wear (10+ years of operation) | Loss of elasticity, inaccurate readings | Scheduled replacement of the thermostat along with the bellows every 8-10 years |
The most common problem is bending the tube during careless defrosting or repairs. For example, if you tried to break off ice with a knife and touched the bellows, it may lose its seal. The part also suffers from aggressive detergents —they corrode the metal and seals.
Replacing the bellows: when to contact a specialist
If the bellows is faulty, it cannot be repaired only replace it. Here's what you need to know:
- 🔧 Independent replacement possible if you have experience working with refrigeration equipment. You will need:
- New bellows (selected according to the refrigerator model)
- Soldering iron and solder (for sealing connections)
- Vacuum pump (for refilling refrigerant)
- 👨🔧 Professional repairs will cost 1,500–4,000 rubles (depending on the model and region). The technician will perform:
- Diagnostics of the thermostat and compressor
- Replacement of the bellows with testing tightness
- Filling the system with freon (if required)
The cost of a new bellows varies from 500 to 2,000 rubles. For popular models (Atlant, Indesit, Samsung), the part can be found in specialized stores (for example, 220-volt.ru or holod-ok.ru). For rare refrigerators (for example Vestfrost or Gorenje over 15 years old) may require an order from an official dealer.
⚠️ Attention: When replacing the bellows, be sure to check state thermostat. In 60% of cases, it also requires replacement, since parts wear out simultaneously.
FAQ: Frequently asked questions about the bellows in the refrigerator
Can a refrigerator be operated with a faulty bellows?
Technically yes, but this will lead to:
- Increased energy consumption (up to 30% above normal)
- Overheating of the compressor and shortening its service life
- Product spoilage due to unstable temperature
We recommend replacing the part within 1–2 weeks after detection of a malfunction.
What refrigerant is used in the bellows?
In most household refrigerators it is:
- Freon R134a (modern models)
- Freon R12 (outdated refrigerators, prohibited for refilling since 2020)
- Isobutane R600a (environmentally friendly option, used in Liebherr, Bosch)
Exact type refrigerant is indicated on the refrigerator nameplate (usually on the back wall).
Why did the new bellows quickly fail?
Probable reasons:
- Defective part (check the warranty)
- Incorrect installation (bent tube, bad soldering)
- Contamination of the system (before replacing the bellows, you need to wash the capillaries)
- Incompatibility with the thermostat (select the part according to the model of the refrigerator!)
Is it possible to lengthen or shorten the bellows with your own hands?
No! The length of the bellows is designed for a specific refrigerator model. Any changes will lead to:
- Incorrect temperature readings
- Refrigerant leakage
- Failure of the thermostat
If the tube too short/long, it means you bought the wrong part.
How often should you check the bellows?
Preventive inspection is recommended:
- Once every 3-5 years for refrigerators older than 10 years
- For any signs of unstable operation (see section “Signs of malfunction”)
- After mechanical damage (falls, impacts)
In modern models with electronic control, the bellows is checked automatically during system diagnostics.