Many owners of household appliances are thinking about the possibility of expanding the deep-freezing zone, especially if the standard volume of the freezer is no longer enough. The question of how to make a full-fledged freezer from a two-compartment refrigerator often arises among those who prepare food for future use or need to store specific goods at low temperatures. Theoretically, such modernization seems simple, but in practice it is associated with serious technical nuances and risks.
The main difficulty lies in the design evaporator and operation thermostat. A standard refrigerator is designed to maintain a positive temperature in the upper chamber, and a minus temperature in the freezer. Trying to "reprogram" the system requires tampering with electrical circuits and understanding the physics of the refrigerant. It is important to immediately note that unopposed cooling of the entire chamber to -18°C can lead to failure of the compressor or deformation of the plastic elements.
In this article we will analyze in detail the physical principles of the operation of the refrigeration circuit, evaluate the feasibility of such actions and consider real ways to increase the volume frosts. We will analyze why simply replacing a thermostat is just the tip of the iceberg, and what hidden problems can arise when operating equipment in abnormal mode. Engineering approach this issue will help to avoid costly mistakes.
Fundamental differences between refrigeration and freezing compartments
To understand whether it is possible to transform one compartment into another, it is necessary to study the design of the refrigeration circuit. In dual-compartment models with one compressor, the refrigerant passes sequentially through the freezer evaporator and then through the refrigerator evaporator. The temperature regime is regulated by dampers and thermostats. If you try to cool the refrigeration compartment to sub-zero values, the system will encounter hydraulic resistance a violation of freon phase transitions.
The key element here is evaporator. In the refrigerator compartment it is often hidden behind the back wall (No Frost system) or is an open coil (drip system). The heat exchange area in the refrigerator compartment is designed to operate at air temperatures from 0 to +10°C. When you try to lower the temperature to -18°C and below, an ice coat will begin to form on the surface of the evaporator much faster than provided by the design.
In addition, thermostat (the thermostat) installed in the refrigeration chamber has a different response range. A conventional thermostat turns off the compressor when it reaches +2...+4°C. The freezer requires a device that opens the circuit at -18...-20°C. Simply replacing the sensor will not solve the problem completely, since the compressor power and condenser volume may not be able to cope with the increased load in the warm compartment.
⚠️ Attention: An attempt to lower the temperature in the refrigerator compartment below 0°C without upgrading the defrost system will lead to ice fouling on the evaporator. This causes overheating of the compressor and eventual breakdown of the unit.
There is also a difference in thermal insulation. The walls of the freezer usually have a thicker layer polyurethane foamto minimize heat gain. In the refrigerator compartment, the insulation is thinner, since the temperature difference with the environment is less. With extreme cooling, the walls will sweat and then become covered with frost on the outside, which will ruin the furniture and floor.
Technical modification methods: replacing the thermostat
The most common method that home craftsmen resort to is replacing the standard thermostat with a analogue with lower operating temperatures. In classic refrigerators (for example Atlant, Biryusa, old models Indesit) the thermostat is located inside the chamber or on the body. Replacing it requires precise selection of the model according to the length of the capillary tube and the type of contacts.
The replacement process is as follows:
- 🔌 Disconnect the refrigerator from the power supply and gain access to thermostat.
- ❄️ Dismantle the old sensor by carefully removing the capillary tube from the evaporator.
- 🛠️ Install a new thermostat (for example, marked K59 or similar, but set to minus values).
- 🌡️ Secure sensitive element on the evaporator of the fridge compartment, ensuring tight contact.
However, even after installing a “freezing” thermostat, the temperature in the chamber may not drop to the required -18°C. This is due to the fact that compressor performance is limited. It simply will not have time to freeze out the increased volume of heat inflow. As a result, the unit will work non-stop, trying to reach the set temperature, which will lead to its rapid wear.
It is important to consider that in modern systems No Frost replacing the thermostat can disrupt the algorithms of the defrost system. The defrosting heating element may turn on too rarely or, conversely, too often, which will lead to either an ice block or defrosting of food. The electronic control (control board) in such models may not correctly perceive signals from the replaced mechanical sensor.
Modernization of the defrost system and humidity control
If you decide to experiment, the issue of moisture removal becomes critical. When the refrigerator compartment operates in freezer mode, moisture from food and air will actively condense and freeze on the evaporator. In normal mode, the refrigerator defrosts with each compressor stop cycle (drip system) or according to a timer (No Frost). In deep freezing mode, these cycles may be insufficient.
It will be necessary to intervene in the operation of defrost timer or the relay. In some cases, craftsmen install an additional timer, which forcibly turns on the defrosting heating element at certain intervals, regardless of the sensor readings. This allows you to melt the ice crust on the evaporator of the refrigerator compartment, turned into a freezer.
| Parameter | Normal mode (Refrigerator) | Upgrade mode (Freezer) | Risk |
|---|---|---|---|
| Evaporator temperature | -5...-10°C | -20...-25°C | Condensate freezing |
| Defrost cycle | Every 8-12 hours | Required every 4-6 hours | Ice accumulation |
| Air humidity | High (products dry out) | Low (products freeze out) | Loss of food quality |
| Compressor load | Normal (KV 30-50%) | Increased (KV 80-100%) | Combustion windings |
It is also worth paying attention to ventilation. In a chamber where the temperature is expected to be below zero, the air circulation should be more intense to avoid the formation of local zones with different temperatures. If your model has only one fan (on the freezer), then the air will stagnate in the fridge compartment, and the thermostat will show incorrect data.
Problems with the compressor and refrigerant
The weakest link with such modernization becomes compressor. It is designed for a certain volume of refrigerant and a certain pressure difference. When operating in double freezer mode, the suction pressure drops and the compression ratio increases. This leads to overheating of the discharge pipe and the motor housing itself.
If the refrigerator operates in the mode continuous cycle (which is inevitable when trying to freeze a large volume), the oil in the compressor may begin to coke or leak into the circuit. This clogs the capillary tube and disables the system. In addition, the refrigerant may not have time to completely evaporate in the evaporator of the refrigeration chamber, and the liquid fraction will enter the compressor, causing water hammer.
In models with an inverter compressor, the situation is even more complicated. The electronics of such units tightly control the shaft rotation speed. An attempt to deceive the system with sensors can lead to a control board error and startup blocking. Inverter systems LG, Samsung or Bosch practically do not lend themselves to such crude modernization without flashing the controller, which is impossible at home.
⚠️ Attention: Operating the compressor in non-stop mode for more than 24 hours without a break for defrosting and rest reduces its service life in 3-4 times. Be prepared to replace the unit soon.
The impact of rework on the safety of products
Even if technically you manage to reduce the temperature, the question of storage quality arises. In a regular refrigerator, humidity is maintained at a level that prevents fruits and vegetables from drying out. In freezer mode (-18°C and below), moisture sublimation occurs. Products that are not vacuum packed will quickly become covered with frost and lose their taste.
In addition, there will be no special freshness zones in the redesigned chamber. Vegetables and fruits, which are usually stored at +4...+6°C, will simply freeze and turn into porridge when defrosted. The cellular structure of plant products is destroyed when ice crystals form. Therefore, turning the entire volume of the refrigerator into a freezer is impractical from a gastronomic point of view.
It is also worth mentioning the smell. At low temperatures, aromas spread differently. If there was fish or meat in the freezer, and dairy products in the refrigeration section, then after the rework, all the contents may acquire a mixed, unpleasant odor. Plastic seals and shelves can also become brittle in the cold.
What happens to bacteria at -18°C?
At a temperature of -18°C, most bacteria go into suspended animation (dormant state), but do not die completely. When defrosted they become active again. Therefore, it is important not only to freeze, but also to properly defrost food.
Alternative and safe solutions
Instead of risky alteration of an existing unit, experts recommend considering more rational ways to solve the problem of lack of space. The household appliances market offers many options that will cost less than repairing a burnt-out compressor after an unsuccessful experiment.
Here is a list of reasonable alternatives:
- 🧊 Buying a separate freezer (chest or vertical). This will solve the volume problem forever.
- 🔄 Replacing the current refrigerator with a Side-by-Side model with an enlarged freezer.
- 📦 Using the services of refrigerated warehouses for seasonal storage of products.
- 🛠️ Professional completion (only for engineers): installation of a second independent cooling circuit, which costs the same as a new refrigerator.
If the goal is just to increase the cold a little, you can try to improve the thermal insulation of the doors, check the seals and clean the condenser at the back. Often the problem of insufficient freezing lies not in the design, but in contamination of the heat exchangers or freon leakage. Diagnostics by a professional technician will be cheaper than buying new equipment.
☑️ Check before alteration
Frequently asked questions (FAQ)
Is it possible to simply turn the thermostat to maximum?
No, this will not help. The mechanical adjustment limit of a conventional thermostat does not allow the temperature in the refrigerator compartment to drop below 0°C. You will simply force the compressor to work continuously until it burns out, but the temperature will not drop above the freezing point of water.
Why does the refrigerator not freeze after replacing the thermostat?
Most likely, the new thermostat does not match the length of the capillary or the type of freon. Also, the reason may be insufficient compressor power to cool the increased volume or a refrigerant leak that appeared after manipulation.
Is it dangerous to store vegetables in a converted freezer?
Yes, it is dangerous. Most vegetables contain a lot of water. When frozen, water expands, destroying cell walls. After defrosting, such vegetables turn into a tasteless slurry and quickly rot. Vegetables need a positive temperature.
How much electricity will the converted refrigerator consume?
Electricity consumption will increase by 2-3 times. The compressor will work almost non-stop, trying to compensate for the heat flow through the insufficiently insulated walls of the refrigerator compartment.