Conversion of the standard converting a refrigerator into a full-fledged freezer is a technically complex task, but can be accomplished with certain skills and tools. Owners of older models often think about such an upgrade in order to increase the storage capacity of frozen foods without purchasing new equipment. However, you should immediately understand that simply adjusting the thermostat will not give the desired result: the design is designed for a different temperature range.
The main difficulty lies in the difference in operating pressures and type of refrigerant. If you try to simply lower the temperature in normal mode, the compressor will work without stopping, which will lead to its rapid overheating and failure. Modernization requires deep intervention in the refrigerant circulation system and changes in thermal insulation.
Before starting work, it is necessary weigh all the risks. Sometimes it makes more economic sense to purchase a separate chest freezer than to spend resources on remodeling. But if the goal is to revive an old unit or obtain a unique volume at minimal cost on the housing, then a technically competent approach will achieve the goal.
Analysis of the technical feasibility of the conversion
The first step is a detailed study of the technical documentation of your model. Not everyone compressor is able to create the pressure necessary to achieve temperatures below -18°C. Refrigerators typically use low-pressure units, while freezers require more powerful systems or specific refrigerants.
Assessing the condition of the insulation is critical. The walls of the refrigerator are thinner than those of the freezer. Without additional insulation, the cold will disappear faster than the system can compensate for it, which will lead to the formation of condensation and ice on the external walls.
⚠️ Attention: An attempt to force a standard compressor to operate in deep freeze mode without replacing the thermostat and refrigerant is guaranteed to burn out the motor windings within several weeks.
It is also necessary to check the integrity evaporator. In refrigerators it is often made in the form of a foam tube or plate element on the back wall. For a freezer, you may need to install a more efficient evaporator evaporator with a larger heat exchange area.
Necessary tools and materials
To perform the work efficiently, you will need specialized equipment, which is rarely found in the household kit. You will need a vacuum pump to remove moisture and air from the system, as well as a pressure gauge station to monitor the pressure during refilling.
The main consumable material will be new refrigerant. Most often used for freezers R134a or R600a, depending on the type of compressor. You will also need solder, flux and a torch for soldering copper tubes.
- 🛠️ Set of pipe cutters and rollers for copper tubes
- 🔥 Gas torch with solder for sealing joints
- 🧪 Vacuum pump and freon cylinder
- 🌡️ New thermostat with a range of up to -24°C
Don't forget about materials to enhance insulation. Polyurethane foam or foil penofol will help reduce heat loss. Without this stage, the efficiency of the alteration will be extremely low.
☑️ Preparation for the alteration
Replacing the thermostat and setting up the system
The standard refrigerator thermostat turns off the compressor when the temperature reaches about +2...+4°C. For the freezer, you need to install a sensor that will open the circuit at -18°C or lower. This is a key element of operating cycle management.
The replacement process involves disconnecting the old sensor and installing a new one in the evaporator. It is important to correctly position the capillary tube of the thermostat so that it accurately reads the temperature of the evaporator, and not the air in the chamber.
After installing the new regulator, an initial test is carried out. The system should reach the specified minimum temperature and shut down correctly. If the compressor is humming, but there is no cold, it may need to be replaced filter drierwhich may have become clogged during previous operation.
Setting the hysteresis (the difference between turning on and off) is also important. A range that is too narrow will result in frequent engine starts, which will shorten its life. Too wide - to temperature fluctuations, which is bad for the products.
Modernization of the evaporator and refrigerant circulation
In most cases, a standard evaporator is not enough for deep freezing. Its area is too small to effectively remove heat at low temperatures. The solution is to install an additional circuit or replace the element with a more powerful one.
When soldering new connections, cleanliness must be observed. Moisture getting inside the copper tube is unacceptable: when it freezes, it will turn into an ice plug that blocks the circulation of freon. That is why the system must be purged with nitrogen.
| Parameter | Refrigerator | Freezer (after modification) |
|---|---|---|
| Boiling point | -10...-15°C | -25...-30°C |
| Suction pressure | Low | Optimal for R134a |
| Compressor operating time | 30-40% of cycle | 60-80% of cycle |
| Type insulation | Standard | Reinforced |
It is important to correctly calculate the length of the capillary tube. It acts as a throttle, creating the necessary pressure difference between the condenser and the evaporator. An error in calculating the length will lead to either insufficient cold or water hammer in the compressor.
Strengthening the thermal insulation of the body
As already mentioned, the walls of a household refrigerator are thin. When operating in freezer mode, the dew point will shift and condensation will begin to form on external metal surfaces. This will lead to corrosion and damage to the floor covering.
To solve the problem, it is necessary to glue the inner walls of the chambers with an additional layer of heat insulation. It has proven itself excellent penofol with a foil layer that reflects thermal radiation back into the chamber.
When laying insulation, be careful not to damage the evaporator tubes if they are located openly. It is also important not to reduce the useful volume so much that the air circulation inside the chamber is disrupted.
⚠️ Attention: The use of flammable materials for insulation (for example, ordinary polystyrene foam without protection) inside an electrical appliance is strictly prohibited due to the risk of fire in the wiring.
Pay special attention to the door seal. Old tires can become hard and no longer hold the cold. The freezer needs a dense, elastic magnetic tape around the entire perimeter.
Refrigerant charging and vacuuming
This is the most critical stage that requires precision. After soldering all the elements, the system is connected to a vacuum pump. The process of pumping out air should last at least 30-40 minutes to completely remove moisture.
Refilling is carried out strictly according to the weight specified in the technical documentation for similar freezing systems. Overfilling freon is just as dangerous as underfilling: in the first case, liquid refrigerant will enter the compressor, in the second, the system will not cool.
Use pressure gauges to control suction and discharge pressure. The readings must correspond to the tables for the selected type of refrigerant at the current ambient temperature.
After filling, all connections are checked with a soap solution or a leak detector for leaks. Even a microscopic hole will eventually lead to a complete loss of freon.
Testing and first launch
The first launch after alteration must be carried out under supervision. Turn on the unit and let it run idle for several hours. Monitor the temperature of the compressor housing: it should not become hot to the point where it is impossible to touch it.
Check the uniformity of cooling throughout the chamber. There should be no areas where the temperature is significantly higher. If all parameters are normal, you can load products, but do not fill the chamber completely on the first day.
During the first week of operation, periodically check for frost on the outer walls and Listen for unusual noises. Stable operation without failures confirms the success of the modernization.
Remember that the compressor life in constant deep freezing mode will be lower than in the normal refrigerator mode. Therefore, regular maintenance and cleaning of the condenser become mandatory.
Is it possible to remake a refrigerator without replacing freon?
Theoretically, you can try to adjust the system to the limit of the standard refrigerant, but the efficiency will be low. The temperature is unlikely to drop below -12...-14°C, which is not enough for long-term storage of meat. The compressor will work for wear.
How long does the entire rework procedure take?
For an experienced technician with all the tools, the process takes from 4 to 8 hours, including time for vacuuming and tests. For a beginner without experience in soldering and working with refrigeration equipment, this may take 1-2 days.
Will the rework pay off financially?
If you already have all the tools (vacuum unit, station, burner) and an old refrigerator, then yes, this is a saving. If you have to buy a tool and call a technician to fill it with freon, the cost of the work may be close to the price of a used freezer.
Which refrigerant is best to use for the conversion?
The most universal and affordable is considered R134a. It is safer than old freons and works more efficiently over a wide temperature range. However, the choice should be based on compatibility with the oil in the compressor.