The idea of converting a chest freezer into a full-fledged refrigerator often arises among small business owners, summer residents or simply enthusiasts trying to save money. Freezers have excellent thermal insulation and airtightness, which makes them an ideal base for creating a device capable of maintaining above-zero temperatures. However, this process requires not only mechanical alteration, but also a deep understanding of the operating principles of the refrigeration circuit.
The main difficulty is that the standard automation of freezers is set to deep minus, usually from -18°C and below. Simply turning the thermostat knob is not enough - the adjustment range is limited by the design of the sensor. To obtain stable +2...+5°C, intervention in the electrical circuit and, possibly, replacement of the refrigerant will be required. This is a task for those who confidently hold a multimeter in their hands and understand the basics thermodynamics.
In this article we will analyze the technical aspects of modernization, including installing an external thermostat and the nuances of compressor operation in new conditions. It is important to immediately note that any manipulations with a sealed circuit require caution. If you plan to leave the sealing system to professionals, then the electrical part can be adapted independently, observing safety precautions when working with high voltage.
Fundamental differences in the refrigeration cycle
To successfully remake the equipment, you need to clearly understand the difference in the operating algorithms of a freezer and a refrigerator. The freezer operates in deep freeze mode, where the compressor rarely turns on but runs for a long time to bring the temperature down to extremes. In the refrigerator, it is necessary to maintain the temperature in a narrow range, which implies more frequent cycles of turning on and off the compressor unit. The key element here is the thermostat (thermostat). Freezers use sensors with a negative response range, for example -10°C to -25°C. If you try to set such a sensor to positive values, it will either not turn off the compressor at all or will not work correctly. That is why replacing or modifying the temperature control circuit is compressor unit.
The key element here is the thermostat. Freezers use sensors with a negative response range, for example -10°C to -25°C. If you try to set such a sensor to positive values, it will either not turn off the compressor at all or will not work correctly. This is why replacing or modifying the temperature control circuit is the most critical stage the whole rework.
⚠️ Attention: The standard freezer thermostat will not physically be able to correctly control the temperature in refrigerator mode. Its spring and membrane are designed for other pressures and temperature expansions of the refrigerant.
It is also worth considering the thermal load. The freezer is usually loaded with food already frozen or in small quantities, while the refrigerator is often loaded with warm food. This requires more power and faster response from the cooling system. If configured incorrectly, the compressor may wear out, which will shorten the service life motor resource.
Necessary tools and materials
For high-quality implementation of the project, you will need not only desire, but also a specific set of tools. Without them, the process may be delayed or lead to equipment damage. Particular attention should be paid to the quality of the purchased components, since the safety and durability of your new unit.
First of all, you will need a new thermostat with a suitable temperature range. Models of the TAM or K series from well-known automation manufacturers have proven themselves well. You also cannot do without a set of plumbing tools, insulating materials and, possibly, new clamps for attaching the capillary tube of the sensor.
- 🛠️ New thermostat with an operating range from 0°C to +10°C.
- 🔧 A set of screwdrivers, pliers and wire cutters for electrical installation.
- 🌡️ External thermometer for calibrating readings inside the chamber.
- 🔌 Wires, terminal blocks and insulating tape.
- 📏 Tape measure or ruler for precise placement of the sensor.
Don't forget to prepare your workplace. You will need good lighting and access to an outlet for testing. If you decide to touch the freon circuit (which is not recommended without a license), you will need a pressure gauge station and a vacuum pump. However, in 90% of cases it is enough to limit yourself to the electrical part.
Selecting and installing a new thermostat
The process of replacing the thermostat begins with dismantling the old device. Usually it is located inside the chamber or on the outer wall, depending on the model of the chest. Carefully disconnect the wires, having previously photographed the connection diagram so as not to get confused when installing a new element. The old sensor is removed from its seat.
The new thermostat is installed in a similar place, but its capillary tube must be pressed tightly to the surface of the evaporator. The accuracy of temperature reading depends on the quality of the contact. Use an aluminum pad or a special heat-conducting paste, if the design allows, to improve heat transfer from the evaporator to the sensor.
☑️ Preparing to install the thermostat
After installation, you need to adjust the adjusting screw. Since the exact values are not known in advance, adjustments are made experimentally. Start the chest, put a thermometer inside and wait until the compressor turns off for the first time. If the shutdown temperature does not correspond to the desired one, (micro-adjustment) of the screw will help to correct the moment of opening the contacts.
Comparison table for operating parameters
To better understand the difference in modes, let's turn to a comparative analysis. The table below shows average values typical for standard household models. This data will help you determine the target indicators when setting up your converted device.
| Parameter | Chest freezer (state) | Refrigerator (target) | Impact on the system |
|---|---|---|---|
| Switch-off temperature | -18°C... -24°C | +2°C... +6°C | Thermostat replacement required |
| Cycle duration | Long operation, rare start | Frequent starts, short operation | The load on the starting unit increases |
| Humidity inside | Low (freezing) | High (condensation) | Risk of corrosion and mold |
| Energy consumption | High at start | Uniform average | Change in energy efficiency class |
As can be seen from the table, the transition to positive temperatures radically changes the nature of the load on the equipment. If the freezer could not turn on for weeks when fully loaded, then the refrigerator will work at a more intense rhythm. This is especially important to consider when choosing starting relay and assessing the condition of the motor windings.
Nuances of working with the refrigerant and circuit
Many craftsmen advise replacing the refrigerant when remaking, arguing that freon, designed for low temperatures, ineffective in refrigerator mode. Indeed, different types of freons (for example, R134a or R600a) have different boiling points and pressures. However, for domestic use, such a replacement is often unnecessary and economically unfeasible.
Standard freon in the freezer when operating in refrigerator mode (at +4°C) will have a very low boiling pressure. This means that the compressor will create a vacuum at the inlet, which is normal operation for many units. The main thing is to ensure the correct operation of the thermostat, which will not allow the system to overcool below the freezing point of water.
Is it possible to change freon yourself?
Replacing the refrigerant yourself requires a license, special tools and skills in soldering copper pipes. In addition, the release of old freon into the atmosphere is prohibited by environmental regulations. If the system has no leaks, there is no need to change the gas - just reconfigure the automation.
If you find that the compressor operates in too short cycles (clocking), this may indicate excess cooling capacity for the new mode. In such cases, sometimes they resort to installing additional throttling or changing the length of the capillary tube, but this is already a level of deep engineering modification that requires accurate calculation hydraulic resistance.
Calibration and testing of the system
After assembling the electrical circuit, the initial startup stage begins. Do not load food into the chamber immediately. Turn on the empty chest and place the thermometer approximately in the middle of the volume. The first cycle of operation may take several hours, since the system must return to operating mode.
Your task is to ensure that the compressor turns off when it reaches +4...+5°C and turns on when the temperature rises to +7...+8°C. If the compressor does not turn off for a long time, the thermostat sensitivity may be too low or the sensor may not be in good contact with the evaporator. Check the tightness of the capillary tube.
- 🕒 Wait for the first automatic shutdown of the compressor.
- 🌡️ Record the temperature at the moment the relay clicks.
- ⏳ Monitor the downtime until the next turn on.
- ❄️ Make sure that food does not freeze at the back walls.
⚠️ Attention: When operating for a long time in refrigerator mode, heavy condensation or frost may form on the inner walls of the chest freezer if the humidity is high. This is due to the fact that the defrosting system (if it was electric) may not be activated at positive temperatures, or, conversely, work too often.
If you notice that the temperature drops below 0°C and the food begins to freeze, you need to slightly turn the thermostat adjusting screw towards increasing the shutdown temperature. Do this in small steps (literally by 10-15 degrees of rotation), since the mechanics of thermostats are very sensitive.
Operation and possible problems
A converted chest will require a change in operating habits. Unlike factory refrigerators, there may not be a full melt water drainage system unless you have modified the drainage. When crossing zero degrees (if the thermostat makes a mistake) or when loading warm products, water may accumulate at the bottom.
It is also worth remembering about the life of the compressor. Frequent operation (short cycle) is more harmful to the engine than long-term operation at full power. Therefore, try not to open the lid of the chest too often and do not keep it open for a long time in order to minimize heat inflows and the number of starts of the unit.
In winter, if the chest is in an unheated room, problems may arise with starting the compressor due to solidification of the oil. In refrigerator mode, this is more critical, since the ambient temperature may be close to the target temperature inside the chamber, and the compressor may simply not turn on when needed.
In conclusion, it is worth noting that converting a chest freezer into a refrigerator is a completely feasible project for a technically literate person. It allows you to get spacious storage with excellent insulation. However, if you are not confident in your abilities when working with electricity, it is better to turn to professionals, since safety always comes before savings.
Frequently asked questions (FAQ)
Is it possible to remake a chest without replacing freon?
Yes, in most cases, replacing the refrigerant is not required. The main task is to change the temperature of the automation. Standard freon (usually R134a or R600a) is able to work effectively even in the positive temperature range if the thermostat is set correctly.
Which thermostat is better to choose for remodeling?
The optimal choice would be universal thermostats of the series TAM-133 or similar ones, which have a wide range of settings. It is important that the operating range includes values from 0°C to +10°C. Avoid specialized freezer thermostats labeled "Deep Freeze".
Will a converted chest consume less electricity?
Not necessarily. Although maintaining a temperature of +4°C requires less energy than -18°C, the frequency of compressor cycles may increase. The final consumption depends on the quality of the insulation, the frequency of opening the lid and the effectiveness of setting the new thermostat.
What to do if the food at the back wall freezes?
This is a sign that the thermostat is set to too low a shutdown temperature. It is necessary to turn the adjusting screw in the direction of increasing temperature (usually clockwise, but depends on the model). Also check whether the capillary tube of the sensor is not too close to the zone of the most intense cold.
Do you need to make a hole for drainage?
In refrigerator mode, condensation will form more actively. If your chest model does not have a standard drain hole (which is typical for many freezers), it is advisable to organize it by drilling the bottom at the lowest point and bringing the tube out, or regularly wipe the chamber manually.