Soldering refrigerator compressor tubes: a complete guide with photos and diagrams

Soldering copper tubes for a refrigerator compressor is one of the most critical operations when repairing refrigeration equipment. Not only the performance of the unit, but also its safety depends on the quality of the connection: improper soldering can lead to freon leakage, compressor overheating, or even fire. This procedure requires precision, special tools and knowledge of the physical processes occurring in the system.

Many self-taught craftsmen are afraid to take on soldering because of the risk of damaging the capillary tube or overheating the oil in the compressor. However, with the right approach and observing the temperature conditions, you can solder tubes even without professional equipment. In this article, we will analyze the entire process from preparation to leak testing, paying special attention to typical mistakes and nuances of working with different brands of refrigerators.

⚠️ Warning: Working with refrigerant and high temperatures requires compliance with safety precautions. If you are not confident in your skills, it is better to contact a specialist - soldering errors can lead to failure of the compressor costing up to 70% of the price of a new refrigerator.

1. When is soldering of compressor tubes required?

Soldering copper tubes is not a routine procedure, but a necessary measure in case of serious malfunctions. The main cases when you can’t do without it:

• 🔧 Mechanical damage pipes (kinks, cracks after moving the refrigerator or dropping heavy objects on the back wall).
• 🧊 Corrosion copper surfaces due to long-term operation in wet conditions (relevant for refrigerators older than 10 years).
• ⚡ Replacement of the compressor —the new unit requires connection to an existing main.
• 🔄 Modernization of the system: installation of an additional filter-drier or bypass.
• 🛠️ Repair after unqualified interventionwhen the previous soldering was performed incorrectly.

It is important to distinguish situations when soldering is really necessary from those where the problem is solved differently. For example, if a refrigerator Atlant or Indesit does not freeze due to a freon leak in the evaporator, soldering the compressor tubes is pointless - you need to look for the leak in another unit. A manometric manifold will help accurately diagnose the malfunction: if the pressure in the system drops to zero in a few minutes, the problem is precisely depressurization.

⚠️ Attention: In refrigerators with a system No Frost (for example, Samsung RL-60 or LG GA-B489) soldering compressor tubes is often accompanied by replacing the thermostat - its contacts may oxidize when heated.

2. Tools and materials: what you will need for work

For high-quality soldering of refrigerator compressor tubes, you will need a specialized tool. It’s not worth saving on it - cheap torches or solders can ruin the whole job. Here is the full list:

Additionally prepare:

• 🧤 Heat-resistant gloves (protection from burns).
• 👓 Goggles with UV protection (when working with a torch).
• 🧲 Magnetic holder for fixing tubes during soldering.
• 📏 Caliper for measuring the diameter of tubes (standard sizes: 6 mm, 8 mm, 10 mm).

Critical: for refrigerators with inverter compressors (for example, Hitachi R-W390P or Mitsubishi Electric MR-SLIM) use only low-temperature solders with a melting point no higher than 200°C - overheating can damage the electronic control unit.

3. Preparation for soldering: disassembling and cleaning the system

Before soldering, you must completely prepare the refrigerator and workspace. Start by unplugging the unit and defrosting it (if it was running). Next:

1. Drain the oil from the compressor (if replacement is required). To do this, turn the refrigerator over with the compressor up and carefully unscrew the filling tube.
2. Purge the system with nitrogen (optional, but recommended to remove moisture). Pressure - 6-8 bar, time - 10-15 minutes.
3. Cut the damaged section of the tube with a pipe cutter, leaving a margin of 10-15 mm for flaring.
4. Clean the soldering area sandpaper (220-400 grit) until shiny - this will remove the oxide film.

Pay special attention to cleaning the inner surface of the tubes. copper or dirt particles can clog the capillary tube, which will lead to increased pressure in the system and overheating of the compressor. For washing, use a special solvent (for example, R-141b) or acetone.

⚠️ Attention: In refrigerators with a system Low Frost (for example, Beko CN 325120), the capillary tube is often soldered directly to the evaporator. When dismantling, do not pull on it - this may tear the heat exchanger from the body.

Make sure that the refrigerator is unplugged for more than 24 hours|Drain the refrigerant through the service port|Mark the pipes (suction/discharge)|Check for spare fittings and seals-->

4. Soldering technology: step-by-step instructions with photos

The process of soldering compressor tubes consists of several stages. The main rule: Do not overheat the joint —the optimal heating temperature is 250–280°C. Exceeding this threshold leads to destruction of the copper structure and the risk of repeated leakage.

Step 1. Flaring the tube

Use an expander to form a socket at the end of the tube. Flaring angle - 45°, depth - 2–3 mm. For tubes with a diameter of 6 mm, cone No. 4 is suitable, for 8 mm - No. 5. Check that the socket fits tightly onto the second tube without play.

Step 2. Applying flux

Use a brush to apply a thin layer of flux to the inner surface of the socket and the outer side of the inserted tube. Excess flux can flow into the system and cause corrosion - remove excess with a napkin.

Step 3. Connecting the tubes

Insert the tube into the socket and secure with a magnetic holder. Make sure that the gap between the surfaces does not exceed 0.1 mm - this is critical for the capillary effect of the solder.

Step 4. Heating and soldering

Turn on the torch and heat the joint, moving the flame in a circle. As soon as the flux starts to bubble (at ~150°C), bring the solder to the seam. It should melt and flow into the gap under the action of capillary forces. Do not blow on the soldering area - this will disrupt the structure of the seam!

Step 5. Cooling

Allow the joint to cool naturally (5-7 minutes). Do not cool with water - this will cause microcracks in the solder. After cooling, remove any remaining flux with a damp cloth.

⚠️ Attention: When soldering compressor tubes Danfoss (installed in refrigerators Electrolux i AEG), avoid getting solder on the unit body - its aluminum coating may be deformed.

What to do if the solder does not flow into the seam?

If the solder does not fill the gap, the reasons may be the following:

1) Insufficient heating (check the temperature with a pyrometer torch).

2) Surface contamination (repeat cleaning and applying flux).

3) The gap between the tubes is too large (redo the flaring).

4) Poor quality solder (use only certified brands).

5. Typical mistakes and how to avoid them

Even experienced craftsmen sometimes make mistakes when soldering compressor tubes. Here are the most common of them and how to prevent them:

• 🔥 Overheating of the tube - leads to annealing of copper and loss of strength. Solution: use a torch with an adjustable flame and thermocouples to control the temperature.
• 💧 Moisture entering the system —causes corrosion and freezing of the capillary. Solution: Purge the system with nitrogen before soldering.
• 🔗 Loose connection —leads to microcracks. Solution: check the flaring with a gauge.
• 🧴 Excess flux —may clog the filter drier. Solution: apply flux in a thin layer.
• ⚡ Live soldering —risk of electric shock. Solution: always unplug the refrigerator 24 hours before work.

One of the most insidious mistakes is the use of tin-lead solder (POS-61) instead of copper-phosphorus. This type of solder oxidizes and crumbles over time, leading to leaks. For refrigeration systems, only solders with a silver content of at least 2% or copper-phosphorus are allowed (for example, CuP6).

⚠️ Attention: In refrigerators with a system Frost Free (for example, Liebert or Whirlpool) after soldering, be sure to replace the filter drier - the old one may be clogged with flux decomposition products.

6. Checking the tightness and filling the system

After soldering, you need to make sure that the system is tight before filling with freon. To do this:

1. Connect the pressure manifold to the service port. compressor.
2. Close all valves and supply nitrogen to the system at a pressure of 15–20 bar.
3. Apply a soap solution to all soldered joints The absence of bubbles within 10 minutes will confirm. tightness.
4. Pump out nitrogen and create a vacuum (depth - at least 500 microns) to remove moisture.

For refilling freon, use only original refrigerantindicated on the compressor nameplate. For example:

• For Atlant i Indesit — R-134a or R-600a.
• For Samsung i LG — R-134a or R-410A (in inverter models).
• For older models (ZIL, Minsk) — R-12 (banned in the EU, but still found in the CIS).

Fill with freon in portions of 30–50 grams, monitoring the pressure of the discharge line:

• For R-134a: 10–12 bar at +25°C.
• For R-600a: 6–8 bar at +25°C.

⚠️ Attention: In refrigerators with linear compressors (for example Secop or Embraco) refill freon only through the service port on the filter drier - direct connection to the discharge tube can damage the valve group.

7. Features of soldering for different brands of refrigerators

The design of pipelines and the type of compressors vary depending on the manufacturer. brands:

For refrigerators Bosch and Siemens with system VitaFresh after soldering, it is necessary to reflash the electronic unit, since it detects a depressurization error. This can be done through the service menu (usually access code #0000 or 1234).

⚠️ Attention: In models Haier and Hisense with function T-ABT (antibacterial coating) you cannot use fluxes based on zinc chloride - they destroy the coating. Use only fluxes based on rosin (for example, F-SW21).

8. Alternative methods of connecting tubes

If soldering is for some reason is impossible (for example, there is no torch or experience), you can use alternative methods of connecting tubes. However, remember that they are less reliable and are only suitable as a temporary solution:

• 🔧 Crimping. fittings (for example, Swagelok) - require special crimping pliers. Suitable for tubes with a diameter of up to 10 mm.
• 🔗 Threaded connectors (for example, Parker) - used with sealing rings made of copper or fluoroplastic.
• 🧲 Epoxy adhesives (for example, Loctite) - only for low-pressure systems (up to 5 bar).
• 🔥 TIG welding - used for thick-walled tubes (from 1.5 mm), but requires professional equipment.

Crimp fittings - the most reliable alternative option. To install them:

1. Place the nut and ferrule on the tube.
2. Insert the tube into the fitting until it stops.
3. Tighten the nut with a torque wrench (tightening torque - 12–15 Nm).
4. Check the tightness with a soap solution.

⚠️ Attention: In refrigerators with a system Dual Cooling (two independent chambers, for example, Samsung RB37J5240) the use of compression fittings on the discharge line is unacceptable - they cannot withstand pressure pulsations.

FAQ: Frequently asked questions about soldering pipes. compressor

Is it possible to solder compressor tubes with a regular soldering iron?

No, the power of a conventional soldering iron (60–100 W) is not enough to heat the copper tubes to the required temperature. In addition, the soldering iron does not provide uniform heating around the entire circumference of the joint, which leads to leaky seams for soldering compressor tubes. be sure to use a gas burner with a flame temperature of at least 1300°C.

Which gas to use in the burner: propane or acetylene?

For soldering copper tubes of the refrigerator, propane-butane (a can with a burner) is optimal. 1900°C, which is enough to melt copper-phosphorus solder. Acetylene (temperatures up to 3100°C) is excessive and can burn copper. The exception is soldering thick-walled tubes (from 1.5 mm) in old Soviet refrigerators, where acetylene is justified.

How much does professional soldering of compressor tubes cost?

The cost of work in service centers depends on the complexity and region:

• Replacement of a section of tube (1 soldering) - 1500–2500 rubles.
• Full re-soldering of the line (3–4 connections) — 3500–5000 rub.
• Soldering + refilling with freon — 4000–7000 rub.

The price usually includes diagnostics, but not always - check before ordering. Self-repair will cost 800–1500 rubles. (price of the torch, solder and flux).

What to do if after soldering the compressor does not start?

There may be several reasons:

1. Airing of the system —re-pumping with a vacuum pump is required (30–40 minutes).
2. Overheating of the compressor —let it cool for 1–2 hours.
3. Incorrect freon charging —check the pressure with a pressure gauge (should be 4–6 bar on the suction tube).
4. Clogged capillary tube —flush the system with solvent R-141b.

If the compressor hums but does not start, the problem may be in the start relay - check it with a tester.

Is it possible to use solder with cadmium for refrigerators?

No, strictly prohibited. Solders with cadmium (for example, PSr-72) are toxic and can cause poisoning if vapors enter the food chamber. In addition, cadmium corrodes over time in the presence of freon, leading to leaks. For refrigeration systems, only copper-phosphorus or silver solders are allowed.