The situation when the refrigerator stops freezing, and a foreign smell or moisture appears inside, often confuses the owner. Diagnostics may reveal the need for a complex procedure, which experts call circuit replacement. Many users do not understand what exactly is hidden behind this term, confusing it with simply filling with gas or replacing the compressor.
In fact, replacement of the circuit this is a major operation to restore the tightness of the cooling system when damage to the evaporator or condenser tubes cannot be repaired locally. This is not just a repair, but an actual reassembly of the “circulatory system” of your refrigeration unit. Understanding the essence of the process will help you make an informed decision about the advisability of restoring the equipment.
In this article we will analyze in detail why such a need arises, how the process of welding tubes occurs and what you should pay attention to when ordering a service. The quality of this work directly affects the further service life of the device.
What is a cooling circuit and why change it
A refrigeration circuit is a closed system of copper or aluminum tubes through which refrigerant circulates. In its normal state, this heat exchanger is completely sealed, and freon, moving from liquid to gaseous and back, takes heat from the chambers. However, over time, the metal is subject to corrosion, mechanical damage or manufacturing defects.
When they talk about the need to replace the circuit, they most often mean installing a new evaporator (“loop”) inside the chamber or overcooking the condenser grid at the back. Old aluminum tubes often burn out due to contact with moisture and salts, forming microscopic fistulas. Local sealing in such cases is ineffective, since corrosion may appear in another place in a week.
The replacement procedure involves removing the old damaged area and welding in a new one. This requires complete evacuation of the system and precise filling freon of a certain type. Without professional equipment, it is impossible to perform this task efficiently, since even microscopic moisture inside the system will lead to blockage of the capillary.
⚠️ Attention: If the technician suggests simply “adding gas” when a leak is detected in the aluminum case, this is a temporary measure. After a short time, gas will escape through the same or a new microcrack.
Main signs of a refrigerant leak
Determine what the problem is lies precisely in the violation of the tightness of the circuit, based on a number of indirect signs. The most obvious symptom is when the compressor is running. The motor hums constantly, without turning off, trying to gain temperature, but there is no effect. lack of cold with the compressor running. The engine hums constantly, without turning off, trying to gain temperature, but there is no effect.
The second important marker is swelling of the rear wall of the refrigerator compartment. In models with a No Frost system or a “crying” evaporator built into a foamed housing, the release of gas from the tubes leads to delamination of the insulation. A characteristic chemical odor or oily stains may also appear on the floor under the unit.
Pay attention to the following symptoms:
- ❄️ The compressor runs non-stop, but the temperature in the chambers is higher than normal.
- 🧊 Swelling or swelling is visible on the back wall of the refrigerator compartment “bubbles”.
- 💧 The appearance of an oily puddle under the refrigerator (oil comes out along with freon).
- 👂 Absence of characteristic gurgling or hissing when the unit is operating.
Diagnostics are best carried out using a leak detector that reacts to the concentration of freon in air. Visual inspection often does not give a complete picture, since a leak can occur in the foamed part of the case.
Replacement technology: sealing the loop and overcooking
The process of restoring tightness depends on the design of the specific refrigerator. In most modern models, the evaporator is made in the form of an aluminum plate or tube mounted in the rear wall. If it is damaged, the wizards use the method of installing an external loop. The old evaporator is cut off, and the new one is hung inside the chamber or attached outside the rear wall.
If we are talking about the condenser (grid at the back), then it is completely replaced. The tubes are carefully unsoldered from the compressor and filter drier. A critical step is to flush the system with high pressure nitrogen. This allows you to remove oil combustion products and possible contaminants remaining after the operation of the old motor.
The stages of work are as follows:
- 🔧 Dismantling the old evaporator or condenser and cleaning the soldering areas.
- 🔥 Installing a new copper or aluminum tube using silver solder.
- 💨 Evacuation of the system for 15-30 minutes to remove moisture.
- ⚖️ Accurate refrigerant filling by weight according to the technical card of the model.
Use silver solder ensures high strength of the seam, which is especially important for vibration loads that the system experiences during compressor operation.
☑️ Quality control of repairs
Comparison of materials: copper versus aluminum
When choosing spare parts or assessing the quality of repairs performed, the question of tube material often arises. Historically, manufacturers used aluminum because of its low cost and good thermal conductivity. However aluminum extremely susceptible to corrosion upon contact with moisture and salts contained in the air and products.
Copper circuits are considered more durable. They are less susceptible to oxidation and are easier to solder, which reduces the likelihood of repeated leakage at the joint. However, copper is more expensive, and not all factory designs allow replacing an aluminum evaporator with a copper one without major alterations.
A comparative table of materials will help you understand the nuances:
| Characteristics | Aluminium | Copper | Steel (rarely) |
|---|---|---|---|
| Thermal conductivity | High | Very high | Low |
| Corrosion resistance | Low (oxidizes) | High | Medium (rusts) |
| Difficulty of soldering | High (special solder required) | Low | Medium |
| Material cost | Low | High | Low |
| Service life | 5-10 years | 15+ years | 10-12 years |
When ordering a circuit replacement service, it makes sense to check with master, what material will be used for the new loop. Switching to copper in models that originally had an aluminum evaporator significantly extends the life of the refrigerator, but requires qualified execution of the joints.
Cost of work and feasibility of repair
The price of replacing the circuit consists of the cost of materials (tube, freon, filter drier, solder) and the complexity of the work. On average, such repairs are classified as expensive. The owner must understand that the cost can reach 40-60% of the price of a new budget-class refrigerator.
It is advisable to carry out repairs if:
- 📅 The refrigerator is less than 7-10 years old.
- 🏆 This is a premium model or a rare vintage copy.
- 🛠 The remaining components (compressor, thermostat, board) are in good working order.
If the unit has served for 15 years, the compressor is worn out, and the housing insulation has lost its properties, replacing the circuit may not be economically justified. In such cases, it is often more profitable to purchase new equipment with a guarantee and a modern energy efficiency class.
⚠️ Attention: Check the final cost before starting work. The price should include not only sealing, but also vacuuming, refilling with freon and a guarantee for work performed for at least 6 months.
Why can’t you save on a filter-drier?
A filter-drier is a disposable item. When the system depressurizes, it absorbs moisture from the air. If the filter is not replaced when replacing the circuit, the accumulated moisture will freeze in the capillary tube, causing an ice block. The refrigerator will stop freezing a few days or weeks after the repair.
Warranty and risks after repair
A high-quality replacement of the circuit allows the refrigerator to operate for many years to come. However, there are risks of repeated failure, especially if the system has not been thoroughly cleaned. The master must provide a written guarantee. Usually it applies to the tightness of the seams and the operation of the compressor after the intervention.
In the first month of operation, it is recommended to periodically check the temperature conditions. If the refrigerator begins to work intermittently or a whistle appears, you must immediately contact service.
Some workshops offer a service for a complete overhaul of the system with the installation of a copper condenser and evaporator. This is the most reliable, but also the most expensive option. Professional approach guarantees that your refrigerator will come back to life and will not become a source of constant problems.
Frequently asked questions (FAQ)
Is it possible to replace the circuit yourself at home?
Theoretically, this is possible if you have welding equipment for non-ferrous metals, a vacuum pump, a pressure gauge station and skills working with freon. However, in practice, without experience, there is a high risk of damaging the compressor or not achieving tightness. In addition, the release of freon into the atmosphere is prohibited by environmental standards.
How long does it take to replace the circuit?
The standard procedure takes from 2 to 4 hours. This time is necessary for dismantling, soldering, long-term nitrogen purging, vacuuming (minimum 20-30 minutes) and refueling. Hasty refueling without proper evacuation will lead to breakdown.
Why does the refrigerator freeze more after replacing the circuit?
Often a new evaporator (loop) has a more efficient heat transfer than an old, partially corroded one. The configuration of the tubes may also be slightly changed. If the temperature drops below normal, you may need to adjust the thermostat or dampers.
Will they provide a warranty if the refrigerator is old?
Many services are wary of taking on equipment older than 10-12 years or give a reduced warranty for it (for example, only on labor, but not on materials). This is due to the high risk of failure of the old compressor after the evacuation and refueling procedure.