Crimping the refrigerator system: purpose, technology and nuances

A refrigerator is not just a household appliance, but a complex technical system where refrigerant circulates under pressure. Over time, even in sealed circuits, microcracks may appear, connections may become loose, or capillary tubes may become clogged. Crimping is a procedure for checking the tightness of the system for leaks, which is carried out both during repairs and for prevention. Without it, it is impossible to guarantee long-term operation of the equipment after replacing the compressor, evaporator or refilling with freon.

Many owners are faced with a situation where the refrigerator stops freezing, and the technician, after diagnosing it, says: “Crimping is needed.” What does this mean in practice? Why can't you just refill the freon and forget about the problem? In this article we will analyze in detail:

• 🔍 What is crimping and how it differs from vacuuming
• ⚙️ When the procedure is mandatoryand when you can do without it
• 🛠️ What tools and materials will be needed for independent crimping
• ⚠️ Typical mistakesthat lead to repeated leaks

What is crimping a refrigerator and why is it needed

Crimping is checking the tightness of the refrigeration circuit by creating excess pressure in it (usually nitrogen or dry air). The procedure simulates operating conditions, but with a margin of safety: if there is even a microscopic crack somewhere, it will appear at a pressure higher than normal. Without pressure testing, refilling freon is pointless: the refrigerant will simply leak out through leaky areas, and the problem will return in a few days.

In refrigeration technology, two types of pressure testing are used:

• 🔵 Primary - carried out after assembling a new refrigerator at the factory or after major repairs (replacement of compressor, evaporator, condenser). The pressure is raised to 15–25 bar (depending on the model) and maintained for 12–24 hours.
• 🟢 Express check —short-term (10–30 minutes) pressure testing 10–12 bar, which helps to quickly find a leak during diagnostics.

It is important to understand: pressure testing does not repair the system, but only detects defects. If a leak is detected, the problem area needs solder, replace or seal special compounds. Only after this can you refill freon.

When pressure testing is required: 5 obvious and non-obvious cases

Many people think that pressure testing is only needed when obvious freon leaks (when the refrigerator does not freeze and the compressor runs non-stop). In fact, there are other situations when the procedure is mandatory:

1. After replacing the compressor. The new unit creates a different pressure in the system, and the old connections may not withstand the load. Crimping checks whether the solder seams have weakened.
2. When repairing an evaporator or condenser. These parts are often damaged by mechanical cleaning or corrosion. Even a small scratch can become a source of leakage.
3. After a long period of inactivity (more than 6 months). In a non-working refrigerator, the seals dry out and the metal can oxidize.
4. When purchasing a used refrigerator. The previous owner may not have noticed the slow leak of freon.
5. After transportation (especially in a horizontal position). Vibrations weaken connections, and even a new refrigerator may require checking.

There are also non-obvious signsthat indirectly indicate a leak:

• 🌡️ The temperature in the chambers unstable (it freezes, then defrosts).
• ❄️ Appears on the back wall ice in atypical places (for example, near the compressor).
• 🔊 Compressor hums louder than usual or works without interruptions.
• 💧 On the floor under the refrigerator oil stains appear (freon is mixed with oil).

How are refrigerators crimped: nitrogen vs air vs freon

For crimping, three types of gases are used, and each has pros and cons:

Nitrogen is the only gas that is recommended by manufacturers (for example, Liebherr and Beko in service manuals they directly indicate the need to use nitrogen pressure testing before refilling freon). Air is possible use only for short-term testing, and freon - as a last resort if there is no nitrogen cylinder at hand.

⚠️ Attention: Never use for crimping oxygen or propane! Oxygen oxidizes the oil in the system, and propane is explosive. Even some self-taught craftsmen make this mistake, which leads to compressor failure.

Step-by-step instructions: how to pressurize a refrigerator yourself

If you decide to carry out pressure testing yourself, you will need:

• 🔧 Nitrogen cylinder (can be rented at a car service).
• 📏 Reducer with pressure gauge (up to 30 bar).
• 🔌 Hoses and adapters for connection to the service port.
• 🔍 Soap solution (to detect leaks).
• 🛠️ Soldering iron and solder (if you find a defect).

Action algorithm:

Turn off the refrigerator and wait for defrosting|Find a service port (usually on the compressor)|Connect the hose from the cylinder to the port|Slowly raise the pressure to 10–12 bar|Apply soap solution to all connections|Maintain pressure 10–15 minutes|If a leak is detected, solder the defect|Repeat the test after repair-->

1. Preparation. Unplug the refrigerator, defrost and drain the water. Find service port (usually this is a copper tube with a cap next to the compressor).
2. Nitrogen connection. Attach the hose from the cylinder to the port through the reducer. Open the valve and slow raise the pressure to 10 bar (for older models Stinol or Biryusa to 8 bar).
3. Looking for leaks. Apply soap solution to all solder joints, tubes and valves. If bubbles appear somewhere, this is a leak. Pay special attention to:
   • 🔹 Compressor soldering areas.
   • 🔹 Evaporator connections (aluminum often cracks).
   • 🔹 Capillary tube (may rub against the body).

Elimination defects. If a leak is found, release nitrogen, solder the crack or replace the damaged part. For soldering, use copper-phosphorus solder (it can withstand high temperatures).

Repeated check. After repair, pressurize the system again and withstand the pressure 15–20 minutes. If the pressure gauge does not show a drop, you can start evacuation and refilling freon.

What to do if there is a leak in the foamed part of the housing?

If the crack is inside the heat-insulating layer (for example, in a no-frost evaporator), you will have to open the caseTo do this:

1. Remove the inner panel of the camera (usually it is secured with latches).

2. Carefully remove the polyurethane foam around the damaged area (you can use a soldering iron or a construction knife).

3. crack and seal the repair area with epoxy resin.

4. Fill the cavity with mounting foam (but do not overdo it - excess foam can deform the tubes).

This process is labor-intensive, and without experience it is better to entrust it to a specialist.

Typical mistakes when crimping and how to avoid them

Even experienced technicians sometimes make mistakes that lead to repeated leaks or breakdown of the compressor. Here are the most common ones:

1. The pressure is too high. If you pump nitrogen higher 25 baryou can break the capillary tube or deform the evaporator. refrigerators Samsung and LG with thin-walled aluminum tubes.
2. Use of moist air. Moisture in the system leads to capillary blockage. Always use compressor corrosion and capillary blockage. Always use dried nitrogen or at least pass air through silica gel.
3. Incomplete check. Many people apply soap solution only to visible connections, but leakage can be:
   • 🔸 In foamed part housing.
   • 🔸 Under rubber seals pipes.
   • 🔸 In Schrader valve (service port).

Soldering. without flux. Without flux for copper solder will not be evenly distributed along the seam, and after a month the leak will return. Flux is suitable for refrigerators F-38N or Castolin 190.

Ignoring vacuuming. After pressure testing, the system needs to vacuum (pump out air and moisture) before filling with freon. Without this, the compressor will quickly fail.

⚠️ Attention: If you pressurize a refrigerator with inverter compressor (for example, Hitachi or Mitsubishi Electric), never increase the pressure above 12 bar. These models are sensitive to water hammer, and a sudden surge in pressure can damage the valves.

How much does it cost? crimping the refrigerator in the service

The cost of the procedure depends on the type of refrigerator, region and complexity of the work. On average in Russia, prices are as follows:

Included in the price usually not included:

• 💰 Freon (paid separately, 500–1 500 ₽ for refilling).
• 🛒 Spare parts (filter drier, tubes, valves).
• 🚚 Craftsman visit (on average 1 000–1 500 ₽).

You can save money if:

• 🔧 Do it yourself defrost refrigerator before the visit technician.
• 📞 Order pressure testing along with other repairs (for example, replacing a compressor).
• 🏢 Contact in brand service center (sometimes there are discounts for owners of equipment Bosch or Electrolux).

⚠️ Attention: Tariff details may vary depending on the service center and refrigerator model. Check the final cost before starting workas some craftsmen inflate prices after diagnostics.

Is it possible to do without crimping: alternative testing methods

Crimping is the most reliable way to check tightness, but in some cases you can use alternative methods:

• 🔍 Leak detector (electronic or ultrasound). hours
  Suitable for detection minor leaks of freon (for example, in systems with R600a). Costs from 5 000 ₽, but the accuracy is lower than that of crimping.
• 💡 Ultraviolet dye.
  It is added to the system along with freon. When there is a leak, the area glows under a UV lamp. Minus: you need to wait until the dye is distributed (up to 24 hours).
• 📉 Control using a pressure gauge.
  If, after refilling freon, the pressure in the system drops by 1–2 hour, this indirectly indicates a leak. But the method will not show where exactly the problem.

When not replace crimping with alternative methods:

• ❌ After replacement of the compressor (risk of damage a new unit).
• ❌ During repairs aluminum tubes (they crack more often, and leaks are difficult to detect without pressure).
• ❌ If refrigerator works on R290 (propane-butane mixture is explosive, and it needs to be checked only with nitrogen).

FAQ: Frequently asked questions about crimping refrigerators

Is it possible to crimp a refrigerator with a conventional pump for tires?

Technically yes, but this it is highly not recommended. The tire pump does not create enough pressure (maximum 8–10 bar), and small leaks may go unnoticed. Moreover, the air from the pump contains moisture, which will then enter the system. If there is no nitrogen cylinder, it is better. using a compressor with a dryer.

How long does the pressure hold during pressure testing?

Minimum check time - 10–15 minutes. But for reliability it is better to withstand the pressure:

• 🔹 1 hour — for household diagnostics.
• 🔹 12–24 hours — after major repairs (compressor replacement, evaporator).

If during this time the pressure on the pressure gauge has not dropped, the system is sealed.

What will happen if you do not perform pressure testing before refilling freon?

The consequences depend on the type of leak:

• 🔸 Minor leak — freon will slowly come out, and after 1–3 month the refrigerator will stop freezing again.
• 🔸 Large leak —the freon will come out beyond several days, and the compressor will work for wear, which will lead to its breakdown.
• 🔸 Oil leakage —if together with freon oil leaks out, the compressor will jam due to lack of lubrication.

In any case, you will have to re-pay pay for diagnostics and repairs.

Is it possible to pressure test a refrigerator with a working one? compressor?

No! Crimping is carried out only on turned off a defrosted refrigerator. If you supply nitrogen to a running system:

• 🔹 The compressor may receive a water hammer (if there is liquid left in the system).
• 🔹 The pressure in the circuit will exceed the norm, and the tubes will burst.
• 🔹 The pressure gauge will show incorrect dataas the compressor will create its own pressure.

Always disconnect the refrigerator from the mains and bleed off the remaining freon before pressure testing.

How often do you need to do preventive pressure testing?

For most refrigerators, preventive pressure testing not requiredif the equipment is working stably. However, there are exceptions:

• 🔹 Refrigerators are older 10 years - once every 3–5 years.
• 🔹 Models with aluminum tubes (for example, Whirlpool or Ardo) - once every 2–3 years.
• 🔹 After moving or strong shaking (even if everything looks normal).

If the refrigerator no-frost, check the tightness at the first signs of unstable operation (for example, if the freezer appears ice).