The compressor is the “heart” of the refrigerator, and its breakdown often means expensive repairs or the purchase of new equipment. However, in 60% of cases, the malfunction is associated with broken windings, oxidation of contacts or damage to tubes, which can be fixed independently by soldering. This procedure requires accuracy, knowledge of electrical basics and compliance with safety precautions, but allows you to save up to 70% of the cost of a new compressor.
In this article we will look at how to properly solder a refrigerator compressor at home: from diagnosing a malfunction to testing after repair. You will learn what tools and materials are needed, how to avoid common mistakes (for example, overheating copper or improperly stripping contacts), and when soldering is useless - for example, when there is an inter-turn short circuit or wear on the piston group. We will pay special attention safety precautions, since working with freon and high voltage is dangerous to life.
1. Diagnosis of a malfunction: when soldering will help and when it won’t
Before you take up the soldering iron, you need to accurately determine the cause of the breakdown. Soldering a refrigerator compressor is advisable only in three cases:
- 🔌 Breakage of windings —the multimeter shows an open circuit (the resistance tends to infinity). Often occurs due to voltage surges or insulation wear.
- 🔥 Oxidation or burnt contacts on the compressor terminal block. Black or green spots and a burning smell are visually noticeable.
- 💧 Cracks in copper tubes (usually at the refrigerant inlet/outlet). It manifests itself as leakage of freon and loss of cold.
If the compressor buzzes, but does not start (interturn short circuit), knocks during operation (piston wear) or overheats in 10-15 minutes (jamming), soldering will not help - the unit will need to be replaced. It is also useless to solder if:
- ⚡ The multimeter shows a short circuit between the windings and the housing (breakdown on weight).
- 🛢️ You can hear oil gurgling in the compressor - this is a sign of crankcase depressurization.
- 🔧 Mechanical damage (cracks, dents) is visible on the housing.
For diagnostics, use a multimeter in continuity or resistance measurement mode. Normal indicators for a working compressor:
| Compressor type | Starting winding resistance (Ohm) | Working winding resistance (Ohm) | Resistance between windings (Ohm) |
|---|---|---|---|
| Danfoss (NL, NF series) | 20–40 | 10–20 | 30–60 |
| Embraco (EG, NE series) | 15–30 | 8–15 | 23–45 |
| Secop (former Danfoss) | 25–50 | 12–25 | 37–75 |
| Mitsubishi, Panasonic | 30–60 | 15–30 | 45–90 |
⚠️ Attention: If the resistance between any winding and the compressor housing is less than 1 MOhm, this is a breakdown to ground. Such a compressor cannot be repaired subject!
2. Tools and materials: what you will need for soldering
For high-quality soldering of the refrigerator compressor, prepare the following set of tools and consumables:
Soldering iron with a power of 100–150 W (for copper tubes) or 40–60 W (for contacts)
Solder POS-61 or POS-40 (for copper) and POS-60 (for contacts)
Flex data-i="93">(for copper) or rosin (for electrical contacts) FKSp (for copper) or rosin (for electrical contacts)
Gas burner (for tubes with a diameter of more than 6 mm)
Pipe cutter or hacksaw for metal
Sandpaper (grain size (for refueling after repair)
Multimeter for checking circuits
Protective gloves and glasses (required!)
Refrigerant R134a or R600a (for refueling after repair)
Vacuum pump (for pumping out the system before refueling)
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Pay special attention to the choice of solder and flux:
- 🔥 For copper tubes use copper-phosphorus solder (for example, CuP-6) or tin-lead POS-61. The latter requires flux FKSp to remove oxides.
- ⚡ Solder electrical contacts Do not use acid fluxes - they cause problems. corrosion! POS-60 with rosin is suitable for
If you have to solder refrigerant pipes, you will additionally need:
- 🛠️ Rolling for crimping tubes after soldering.
- 🧪 Nitrogen (in a can) for purging the system before soldering (prevents oxidation).
- 📏 Template for bending tubes (to avoid creases).
⚠️ Attention: When soldering tubes with freon it is strictly forbidden to heat them to temperatures above 150°C - this leads to decomposition of the refrigerant and the formation of toxic gases. Use heat-dissipating clamps or a wet rag to cool adjacent areas.
3. Preparing the compressor for soldering: disassembling and cleaning
Before soldering, the compressor must be removed from the refrigerator and prepared. Follow this. algorithm:
- Disconnect the refrigerator from the mains and discharge the capacitor (short-circuit its terminals with a screwdriver with an insulated handle).
- Drain the freon through the service port (if the system is charged, to do this, connect the pressure gauge manifold and bleed the gas in a well-ventilated area or on). street.
- Disconnect the compressor from the system:
- Cut the pipes with a pipe cutter at a distance of 10–15 cm from the compressor.
- Unsolder or unscrew the power terminals (remember their location!).
- Remove the mounting bolts and remove the compressor.
- Remove remaining oil and dirt from the tubes with a solvent (acetone or white spirit).
- Sand the contacts and soldering areas with sandpaper until shiny.
- Blow the tubes with nitrogen to remove moisture.
If soldering is required for electrical contacts (terminal block), additionally:
- 🔍 Check the integrity of the wire insulation. If melted, replace them with heat-resistant ones (for example, PVKV).
- 🧲 Remove oxides from the terminals with a metal brush or file.
4. Soldering technology: step-by-step instructions
The soldering process depends on the type of damage. Below are instructions for the three most common cases.
4.1. Soldering broken compressor windings
If the multimeter showed a break in the winding, proceed as follows:
- Find the break point:
- Visually inspect the windings for blackened or melted areas.
- Ring each section of the winding separately (starting, working, common point).
- Clean the soldering area:
- Remove the varnish insulation from the wire with a knife or sandpaper.
- Treat the surface with flux (rosin or FKSp).
- Solder winding:
- Use a 40–60 W soldering iron and solder POS-60.
- Heat the soldering area to the melting temperature of the solder (180–220°C).
- Apply solder, ensuring uniform coverage.
- Coat the soldering with varnish UR-231 or heat shrink tube.
- Check the integrity with a multimeter circuits.
4.2. Soldering copper tubes of the compressor
For cracks or broken tubes, use gas torch copper-phosphorus solder:
- Prepare the tubes:
- Cut the damaged area with a pipe cutter.
- Sand the edges with sandpaper and treat with flux FKSp.
- Connect the tubes:
- Put a heat-shrink sleeve on one of the tubes (for additional sealing).
- Insert the tubes into each other (the gap is no more than 0.1 mm) or use a connecting sleeve.
- Warm up the soldering area:
- Heat evenly with a torch to a temperature of 600–700°C (the solder should spread throughout the capillary).
- Allow to cool naturally (do not cool with water!).
- Pump into the system nitrogen under pressure of 10–15 atm and check with a soap solution for leaks.
- Remove the terminal cover and clean the contacts with a file.
- Apply flux (rosin) and tin the contacts with a soldering iron.
- Solder new wires, observing polarity (usually there is a marking on the compressor:
C- common,S- starting winding,R- working). - Check the resistance between the contacts with a multimeter (must correspond to the table in section 1).
What to do if the solder does not stick to copper?
If the solder rolls off or does not stick, the reason may be:
1. Insufficient heating —copper must be heated to the melting temperature of the solder (for POS-61 this is ~190°C).
2. Poor cleaning —remove oxides with a metal brush and repeat flux treatment.
3. Incorrect flux —for copper, use only FKSp or boric acid, rosin is not suitable.
4. Surface contamination —wipe the soldering area with acetone before heating.
4.3. Soldering terminal block contacts
Oxidized or burnt contacts are restored as follows:
5. Typical errors and how to avoid them
Even experienced craftsmen make mistakes when soldering compressors. Here are the most common ones and ways to prevent them:
| Error | Consequences | How to avoid |
|---|---|---|
| Overheating of tubes | Copper deformation, freon leakage, scale formation | Use heat-dissipating clamps, heat evenly |
| Use of acid flux | Copper corrosion, repeated leakage after 1–2 years | Use only FKSp or boric acid |
| Insufficient cleaning before soldering | Poor solder adhesion, weak connection | Clean the surface until shiny, use acetone |
| Soldering under freon pressure | Explosion and fire hazard, gas poisoning | Always bleed off the refrigerant before heating! |
| Wrong polarity when soldering contacts | Short circuit, burning of windings | Check the connection diagram according to the compressor marking |
Another common problem is cold. soldering (when the solder has not fused to the base, but simply stuck on top). To avoid this:
- 🔥 Heat the soldering area from below (through the copper), and not the solder from above.
- 🕒 Give the solder time to spread (do not blow or move details).
- 🔍 After cooling, check the soldering for strength - pull the tube or wire.
⚠️ Attention: If after soldering the tubes you find microcracks (for example, when checking with nitrogen), do not try to solder them over the old seam. Cut off the damaged area and build a new tube using. couplings.
6. Charging the system after soldering: step-by-step process
After successful soldering, the compressor needs to be installed back and the system refilled with refrigerant. This stage is critical - errors lead to repeated failure.
Algorithm of actions:
- Install the compressor in place and secure with bolts. Connect the tubes using a crimping tool.
- Connect the vacuum pump to the service port:
- Pump out the system until pressure
-1 bar(vacuum). - Keep the pump on for 15–20 minutes to remove moisture.
- Pump out the system until pressure
- Fill the refrigerant:
- Connect the cylinder with freon (R134a for modern models, R600a for old ones).
- Refill in portions of 20–30 grams, monitoring the pressure with a pressure gauge (norm for R134a: 4–6 atm on the high pressure side).
- Turn on the refrigerator and wait until the compressor starts.
- Check the temperature in the chambers (should drop to +4...+6°C in 1–2 hours).
- Check the tubes for freezing - condensate should cover evenly evaporator.
The volume of freon for refilling depends on the refrigerator model. Approximate values:
- 🍺 Single-chamber refrigerators: 30–60 grams.
- 🧊 Double-chamber (with one compressor): 80–120 grams.
- ❄️ Systems No Frost: 100–150 grams.
⚠️ Attention: When refilling R600a (isobutane), remember that this refrigerant is explosive. Work! in a ventilated area, without open flames and sparks.
7. Testing the compressor after repair
To ensure the success of the repair, carry out a comprehensive check:
- Ring the windings with a multimeter:
- Resistance must correspond to the passport values (see table in section 1).
- Check for absence of breakdown on the case (resistance >1 MOhm).
- Measure current consumption:
- Connect the compressor via current clamps.
- Normal starting current: 1.5–2.5 A (for household models).
- Operating current: 0.8–1.2 A. If higher, interturn short circuits are possible.
- Check pressure:
- On the suction side (low pressure): 0.5–1.5 atm.
- On the discharge side (high pressure): 8–12 atm (for R134a).
- After 2 hours of operation, temperature in the freezer there should be
-18...-20°C. - The compressor should turn off after 8-12 minutes of operation (40-60% cycle).
If the compressor does not startcheck:
- 🔌 Correct connection of the starting relay (contacts
SandCmust be closed at the time of start). - 📊 Network voltage (should be 220–230 V, with reduced voltage the compressor will not starts).
- 🔋 Capacity of the starting capacitor (check with a multimeter in capacitance measurement mode).
8. When soldering is impractical: signs of non-repairability
Soldering of a refrigerator compressor is not always justified. Here are the signs when it is better to replace the unit or refrigerator:
- 🔊 Knock or grinding during operation - a sign of wear of the piston group or bearings.
- 🌡️ Case overheating up to 80–90°C after 5–10 minutes of operation (norm: 50–60°C).
- 💥 Breakdown to the housing (resistance between windings and metal <1 MOhm).
- 🔄 Frequent on/off (cycle less than 2 minutes) - a sign of an interturn short circuit.
- 🛢️ Leakage oil from the crankcase (visible through the inspection window or by oil stains under the compressor).
Also, soldering is useless if:
- 🕰️ The refrigerator is more than 10 years old - a new compressor can cost 50-70% of the price of the equipment.
- 🔧 Compressor inverter type - its electronic board often fails during power surges.
- 🧊 The system uses refrigerant R12 or R22 —these freons are prohibited for refilling in domestic conditions.
Cost of a new compressor for household refrigerators (Danfoss, Embraco) - from 4,000 to 12,000 rubles. If you add the work of a master (3,000–6,000 rubles), the repair costs 7,000–18,000 rubles. For comparison, budget refrigerators (ATLANT, Biryusa) cost from 15,000 rubles. Thus, soldering is advisable only if minor damage (winding break, tube crack) and if the refrigerator is younger than 7–8 years.
⚠️ Attention: Compressor parts (such as piston rings or valves) are not sold separately. If the diagnostics showed mechanical wear, you will have to change the entire assembly.
FAQ: Answers to frequently asked questions
Is it possible to solder the compressor without draining the freon?
No! Freon under pressure is explosive when heated. Even if there is some refrigerant left in the system, it must be released through the service port. Work in a ventilated area or outdoors.
Which solder is best for soldering compressor tubes?
For copper tubes it is optimal copper-phosphorus solder (for example, CuP-6) - it does not require flux and can withstand high temperatures. Suitable for soldering with flux POS-61 (tin-lead). Do not use solders with cadmium - they are toxic!
How long does it take to solder a compressor?
Soldering itself takes 30–60 minutes. But taking into account diagnostics, refilling freon and testing, the whole process takes 3–5 hours. If you are a beginner, allow yourself 6-8 hours.
Is it possible to solder aluminum compressor tubes?
Soldering aluminum requires a special flux (for example, F-34A) and high-temperature solder (HTS-2000). In domestic conditions this is difficult, so it is better to use copper-aluminum adapters with crimping.
What to do if after soldering the compressor does not start?
Check:
- Correct connection of the starting relay (contacts
SandC). - Network voltage (should be 220–230 V).
- Capacity of the starting capacitor (call with a multimeter).
- The integrity of the thermorelay (close the contacts directly - if the compressor starts, the relay is faulty).
If everything is in order, but the compressor is humming and does not start, it is possible interturn short circuit (replacement required).