What length of the capillary tube should be in the refrigerator: standards, calculations and nuances of replacement

The capillary tube is one of the key elements of the refrigeration circuit, on which the efficiency of the compressor and the temperature stability in the chambers directly depend. Its length is not accidental: a tube that is too short will lead to excess freon pressure and overheating of the system, and a tube that is too long will lead to insufficient cooling and increased load on the compressor. However, there is no universal value: the parameter depends on the model of the refrigerator, the type of refrigerant, the compressor power and even climatic operating conditions.

If you are faced with the need to replace the capillary tube (for example, due to blockage, mechanical damage or after repair of the circuit), it is important to understand how to choose the right length. An error in calculations can result in a compressor breakdown in just a few months. In this article, we will look at what length standards exist for popular brands (Indesit, Atlant, Samsung, LG etc.), how to measure the tube yourself and what to do if the original part is not available.

Why do you need a capillary tube in the refrigerator and how does it work

The capillary tube plays a role throttler device —it reduces the pressure of the refrigerant before it enters the evaporator. Unlike a thermostatic valve (TRV), a capillary is simpler and cheaper, therefore it is used in most household refrigerators. The principle of operation is based on a physical effect: when passing through a narrow section of the tube, freon loses pressure, cools and goes into the liquid-gas phase necessary to absorb heat in the evaporator.

Key functions of the capillary tube:

• 🔹 Adjusting the refrigerant flow - ensures uniform distribution freon through the evaporator.
• 🔹 Maintaining pressure difference between the condenser (high pressure) and the evaporator (low).
• 🔹 Compressor protection from water hammer (liquid freon entering cylinder).
• 🔹 Optimization of energy consumption —the correct length reduces the load on the system.

Interestingly, the length of the tube is directly related to it inner diameter (usually from 0.6 to 1.2 mm). The thinner the tube, the longer it must be to create the same resistance to flow. For example, in refrigerators Atlant tubes with a diameter of 0.7–0.8 mm and a length of 2–3 meters are often used, and in models Liebert with powerful compressors - up to 4–5 meters.

Standard capillary tube lengths for popular brands

Refrigerator manufacturers rarely indicate the exact length of the capillary tube in the technical documentation, but there are average values for different brands and types of systems. Below is a table with approximate data for household models. Please note that actual parameters may differ by ±10–15% depending on the modification and year of manufacture.

Critical error: using a tube of the wrong length can lead to an increase in the temperature in the chamber by 5-10°C within 1-2 weeks after repair. For example, if in a refrigerator Indesit with R134a, install a 1.5 m long tube instead recommended 2.2 m, the compressor will work without stopping, and the evaporator will be covered with ice.

⚠️ Attention: The data in the table is for reference only. To accurately select the length of the tube, always check the service manual for your specific model or consult with a refrigeration equipment repair technician. Parameters may vary depending on the modification of the compressor and the type of cooling system.

How to measure the length of a capillary tube at home

If the original tube is damaged or lost, its length can be restored independently. For this you will need:

• 📏 Tape measure or measuring tape (preferably metal).
• 🔧 Pliers or pipe bender (for careful removal).
• 🧲 Magnet (for finding a tube in the thermal insulation).
• 📝 Notepad for notes.

Procedure:

1. Unplug the refrigerator and defrost it for 12-24 hours.
2. Remove the back panel (in most models the tube runs along the condenser).
3. Find capillary tube - it is thinner than the others (diameter ~0.7 mm) and is usually soldered to the filter-drier.
4. Carefully disconnect the tube from the filter and condenser without bending it.
5. Straighten the tube and measure its length from beginning to end (including bends!).

Disconnect the refrigerator from the outlet

Make sure there is no freon in the system (the tube should not be cold)

Prepare tools for careful dismantling

Write down the brand and model of the refrigerator to clarify the data-->

Important: if the tube passes inside the thermal insulation of the case (as in models Samsung with a hidden capacitor), it will have to be removed through special technological holes. In this case, it is better to entrust the work to a professional - the risk of damaging the insulation or circuit is too high.

How to calculate the length of the capillary tube when replacing

If the original tube is lost or its length is unknown, you can use empirical formulaswhich is used by refrigerator repair technicians. Main parameters for calculation:

• 🔹 Compressor power (in watts).
• 🔹 Refrigerant type (R134a, R600a, etc.).
• 🔹 Tube diameter (measured with a caliper).
• 🔹 Temperature conditions (single-chamber/double-chamber refrigerator).

Simplified formula:

Length (m) = (Compressor power (W) × Refrigerant coefficient) / Diameter² (mm)

Where is the refrigerant coefficient:

• R134a — 0.045
• R600a — 0.038
• R404a — 0.052

Calculation example for refrigerator Atlant MXM-1808:

Compressor power - 120 W, refrigerant R600a, tube diameter - 0.7 mm.

Length = (120 × 0.038) / (0.7)² ≈ 2.55 m

⚠️ Attention: The formula gives an approximate value! To accurately select the length, be sure to consider:

1. The length of the condenser (the longer it is, the shorter the capillary can be).
2. The presence of additional heat exchangers (in models with No Frost, the tube is 20–30% longer).
3. Climatic conditions (in hot climates, the length increases by 10–15%).

What happens if you choose the wrong length capillary tube

Errors when choosing the length of the tube do not appear immediately, but after 1–4 weeks of operation. Symptoms depend on whether the part is shorter or longer:

It is especially dangerous a short tube —it leads to overheating of the compressor and its failure within 3–6 months. For example, in refrigerators Samsung with inverter compressors, an incorrect tube length can cause an error E1 (problem with the temperature sensor) within a week.

What to do if after replacing the tube the refrigerator does not cool?

If the refrigerator does not freeze after replacing the capillary tube, check:

1. Tightness of solder joints (possible freon leakage).

2. Correct refrigerant charging (undercharging or overcharging).

3. Condition of the filter drier (it could fail if overheated).

4. The operation of the thermostat (perhaps it turns off the compressor ahead of time).

In 80% of cases, the problem is solved by repeated evacuation of the system and correct refilling of freon.

How to replace the capillary tube yourself: step-by-step instructions

Replacing the tube requires care and compliance with safety precautions. If you are not confident in your soldering skills and working with refrigerants, it is better to contact a specialist. For self-repair you will need:

• 🔥 Gas torch or blowtorch.
• 🛠️ Solder (copper-phosphorus or silver).
• 🧪 Vacuum pump (for pumping air out of the system).
• ⚖️ Scales for refilling freon.
• 🧤 Protective gloves and glasses.

Step-by-step algorithm:

1. Draining freon. Cut the tube at the filter drier and release the refrigerant in a well-ventilated area (or use recuperator).
2. Removing the old tube. Unsolder it from the condenser and evaporator. If the tube passes through thermal insulation, carefully remove it without damaging the foam.
3. Installing a new one tubes. Lay it along the same route, avoiding sharp bends (bending radius - at least 5 cm).
4. Soldering connections. Use flux for copper and heat the soldering area evenly. Do not overheat the tube - this will narrow its lumen!
5. Evacuate the system. Connect the vacuum pump for 15–20 minutes to remove moisture and air.
6. Refilling freon. Fill the refrigerant according to weight (indicated on the nameplate on the compressor). For R600a, 40–80 grams are enough, for R134a - 80–150 grams.
7. Check tightness. Apply a soap solution to the connections - if there are no bubbles, the system is sealed.

After refueling, turn on the refrigerator and check the temperature in the chambers after 6–8 hours. If the compressor operates in cycles (turns on for 10–15 minutes, turns off for 20–30 minutes), and the temperature is stable, the repair was successful.

Where to buy a capillary tube and how to choose a quality part

Capillary tubes are sold in specialized stores of spare parts for refrigerators or on online sites (for example AliExpress, eBay, Avito). When purchasing, pay attention to:

• 🔹 Material —only copper grade M1 or M2 (without impurities).
• 🔹 Wall thickness —at least 0.1 mm (thin-walled tubes burst when soldering).
• 🔹 Internal diameter —measure with a caliper (tolerance ±0.01 mm).
• 🔹 Coil length —take with a margin of 0.5–1 m for bends and soldering.
• 🔹 Manufacturer —reliable brands: Copper Tube, KME, Mueller.

The cost of 1 meter of copper capillary tube with a diameter of 0.7 mm - from 150 to 400 rubles (for 2026). Cheap analogues (made in China) may have uneven wall thickness, which will lead to blockages or ruptures.

⚠️ Attention: Before purchasing, check with the seller for a quality certificate for copper. Counterfeits made from alloys with a high content of zinc or aluminum cannot withstand freon pressure and burst when soldered.

If you cannot find a tube of the required diameter, you can use the closest analogue, but then you will have to adjust the length:

• If diameter more by 0.1 mm - increase the length by 10-15%.
• If the diameter smaller by 0.1 mm - reduce the length by 10-15%.

FAQ: Frequently asked questions about capillary tubes in refrigerators

Is it possible to shorten a capillary tube if it is too long?

It is possible to shorten the tube, but this requires precise calculation. Every 10 cm of length affects the freon pressure by 0.1–0.3 bar. If you shorten the pipe by 30–50 cm without adjusting other parameters (for example, the amount of refrigerant), the compressor will work with overload. It is better to choose a tube of the required length or compensate for the shortening by installing an additional filter-drier.

Why does the capillary tube become clogged, and how to prevent it?

The main causes of blockages:

1. Moisture entering the system (copper oxidation).
2. Decomposition of compressor oil (forms tarry deposits).
3. Mechanical particles (chips after soldering).

For prevention, use a high-quality filter drier and vacuum the system for at least 15 minutes before charging freon.

Is it possible to replace capillary tube to a thermostatic expansion valve (TRV)?

Theoretically, yes, but this will require a complete rework of the system:

• Replacement of the receiver (if there is one).
• Installation of a temperature sensor for the expansion valve.
• Reconfiguration pressure in the circuit.

Such an upgrade is justified only for powerful commercial refrigerators. In household models, it will lead to an increase in the cost of repairs by 3–5 times without significant benefit.

How to check that the capillary tube is clogged?

Signs of a blockage:

• The compressor works non-stop, but the refrigerator does not freeze.
• The condenser is cold (no heating).
• The tube at the filter-drier is icy, and then warm.

For diagnostics, disconnect the tube from the filter and blow it with nitrogen. If the gas does not pass through, the blockage is confirmed.

Which capillary tube is better: copper or aluminum?

Used in refrigerators only copper. Aluminum is not suitable for several reasons:

• Low corrosion resistance (interacts with freon).
• Difficulty of soldering (special fluxes are required).
• High risk of oxidation and blockages.

An exception is some industrial systems, but even there aluminum is used only for areas with low pressure.