Many owners of country houses or rented apartments are faced with a situation where there is little free space in the kitchen, and the chest freezer, which occupies half the corridor, is used ineffectively. The idea often arises of using a powerful freezer for storing fresh food, vegetables and drinks, but the standard operating mode does not allow raising the temperature above -18°C without the risk of spoiling the contents. Converting a chest freezer into a refrigerator This is a real task that you can solve with your own hands if you understand the principles of operation of the compressor and defrosting system.
The main difficulty lies not in the cooling itself, which the freezer provides in abundance, but in organizing the correct defrosting cycle and accurately maintaining above-zero temperatures. If you simply change the settings, the evaporator will be covered with a “coat” of ice, and the compressor will work without stopping, consuming a huge amount of electricity. In this article, we will analyze the technical nuances of replacing a thermostat and implementing an automatic defrosting system.
Before you start opening the case and interfering with the electrical circuit, you must clearly understand that you are making changes to the standard design of the electrical appliance. Factory warranty for such devices, in case of self-repair, it will be canceled. However, if the chest has been serving faithfully for many years, and its resource allows it to continue working, competent modernization can extend its life in a new quality.
Fundamental differences between a freezer and a refrigerator
At first glance, it may seem that the difference between these devices is minimal: both There is a compressor, a condenser, a capillary tube and an evaporator. However, their operating modes are radically different. Freezer compartment designed to quickly freeze moisture from food and maintain a consistently low temperature, often ignoring short-term increases when opening the door. The evaporator in chests is usually located around the perimeter of the inner box or under its bottom.
In normal refrigerator the temperature is kept in the range from +2 to +8°C. The main difference lies in the cyclicity of work and the moisture removal system. In refrigerators with a No Frost system or even in static models with a drip defrost system, moisture should not turn into an ice shell on the evaporator. In the freezer, the formation of frost is a standard mode, which is removed only with complete manual defrosting.
⚠️ Attention: An attempt to use the freezer as a refrigerator without setting the defrost timer will lead to freezing of the evaporator in 2-3 days. This will cause the compressor to overheat and cause premature failure.
The key element that will have to be replaced is the thermostat. Freezers use thermostats with a range from -10 to -24°C (for example, K59-L1275), while for refrigeration mode, sensors operating in the positive range are needed (for example, TAM-133 or analogue K50). It is also critical to consider the length of the thermostat capillary tube, since this determines the accuracy of temperature reading in different zones of the chamber.
Necessary tools and components
To successfully implement the project, you will need to prepare not only the chest freezer itself, but also a number of specific parts. Without a high-quality defrost timer (defroster) and a new thermostat, there is no point in starting work. These components will be responsible for automatically switching between the “cooling” and “defrosting” modes, simulating the operation of the factory electronics of modern refrigerators.
You will need a standard home repair kit, supplemented with measuring instruments. Pay special attention to safety, since the work will be carried out with a mains voltage of 220V. All connections must be insulated and grounding checked.
List of required materials:
- 🔧 New thermostat with a range of +2...+10°C (necessarily with a long capillary pipe).
- ⏱️ Defrost timer (defroster) mechanical or electronic on 220V.
- 💡 Defrost heating element (if the chest design does not provide a built-in evaporator heater).
- 🔌 Terminal block, heat shrink and wires with a cross-section of at least 0.75 mm².
- 🌡️ External thermometer for calibrating settings.
⚠️ Attention: When purchasing a defrosting heating element, make sure that its power and dimensions are suitable for installation in your chest. A heater that is too powerful can melt the plastic box or damage the seals.
Don't forget about the tools: a multimeter for checking circuits, screwdrivers, wire cutters, electrical tape and possibly a dremel or hacksaw for carefully installing new elements into the case. If you plan to attach the heating element to the evaporator, you will need a heat-resistant sealant or aluminum tape to improve heat transfer.
☑️ Check before starting work
Selecting and installing a new thermostat
The most important stage of the remodeling is replacing the “brain” of the system, that is, the thermostat. As already mentioned, the standard freezer regulator will not allow the temperature to rise above zero. You need to purchase an analogue designed for refrigerators. Popular models, such as TAM-133, TAM-145 or K50-L1950, have a working range ideal for storing vegetables and dairy products.
When installing, pay attention to the length of the capillary tube. In chest freezers, the evaporator is often located far from where the standard thermostat is installed. If the new regulator tube is short, you will have to carefully extend it or place the sensor in close proximity to the evaporator, leading the control knob out through an additional hole. The mounting location of the sensitive element on the evaporator must be cleaned of paint and treated with heat-conducting paste.
The connection diagram, as a rule, remains standard: opening the compressor circuit when the set temperature is reached. However, unlike a freezer, where the thermostat opens the circuit at -20°C, the new sensor will do this at +4...+6°C. This will ensure an economical operating mode.
Nuances of setting the differential
Some thermostats have a differential adjustment screw (the difference between turning on and off). For refrigeration mode from a chest, it is advisable to set the differential to about 2-3 degrees so that the compressor does not click too often.
After installation, be sure to conduct a test run without food. Connect an external thermometer and wait until the compressor switches off for the first time. Record the temperature and compare with the readings on the regulator handle. If the scatter is large, it may be necessary to recalibrate or replace the sensor with a more suitable one.
Organizing automatic defrosting of the evaporator
Without a defrosting system, your new “refrigerator” will turn into a block of ice. In freezers, moisture from food settles on the cold walls and freezes. It should drain in the refrigerator. To implement this process, it is necessary to introduce defrost timer a heating element into the circuit.
The logic of the system is as follows: the timer counts the operating time of the compressor (for example, 6 hours). After that, he switches the circuit: turns off the compressor and turns on the defrost heating element. The heater operates until the defrost completion sensor (thermal contact) opens the circuit when the temperature reaches about +10°C. Then the timer starts the cooling cycle again.
Installing the heating element requires caution. It must be secured to the evaporator in such a way that the heat is evenly distributed over the surface, but the heating element itself does not touch the plastic of the box. Aluminum tape or special clamps are often used. It is important to ensure condensate drainage: in the bottom of the chest (if the design allows it) or in the lower part of the evaporator, you need to organize the flow of water into a dropper above the compressor, where it will evaporate.
There are electronic defrost controllers that allow you to flexibly adjust the heating intervals and duration. They are more compact than mechanical timers and can be installed outside the chest, making settings easier to access. Mechanical timers are more reliable, but require more space for insertion into the case.
Electrical connection diagram and installation
Assembling an electrical circuit is a crucial moment that requires care. Carry out all work only with the device completely disconnected from the network. The basic circuit includes a serial connection: network → defrost timer → (branch 1: compressor + fan if any) and (branch 2: defrost heating element + thermal contact).
For clarity, consider the simplified connection logic in the table:
| Component | Function in the circuit | Connection point |
|---|---|---|
| Defrost timer | Mode switch | Into the break in the phase wire to the compressor |
| Thermostat (new) | Temperature control | Into the compressor power supply circuit (after the timer) |
| Defrost heating element | Evaporator heating | Parallel to the compressor (via timer contacts) |
| Thermal contact | Overheat protection | Series with the heating element |
All twists must be replaced with soldering or connected via terminal blocks. Wires passing near the heating element must be in heat-resistant insulation (for example, fiberglass). Sagging wires that may touch the heating element are not allowed.
After assembling all connections, before connecting to the network, “ring” the circuit with a multimeter for a short circuit. Make sure that the body of the chest does not “ring” with the phase. Only after a successful test can power be supplied.
Temperature setting and testing
The converted device must be started in idle mode. Load the chest with water bottles to create a heat load that simulates the food. Set the thermostat knob to the middle position. During the first day of operation, monitor the on and off cycles.
The normal mode is one in which the compressor runs for about 10-15 minutes and rests for 20-30 minutes (depending on the ambient temperature). The temperature inside should stabilize within +3...+7°C. If the temperature drops below freezing, check your thermostat settings. If it rises above +10°C, there may be not enough refrigerant or the sensor is incorrectly selected.
Pay special attention to the operation of the defrosting system. After 6-8 hours of operation, the heating element should turn on. You may hear the characteristic cracking sound of ice or see steam. Make sure that the water flows to the intended place and does not flow out through the cracks.
Possible problems and ways to solve them
During operation, nuances may arise related to the individual characteristics of a particular chest. For example, due to the large thermal insulation and volume of the chamber, the temperature in different corners may differ. It may be warmer in the upper layers, and colder at the bottom.
It is recommended to use air circulation to equalize the temperature. If the lara does not have a built-in fan, you can install a small computer cooler (12V) powered by a separate unit, which will operate continuously or cyclically. This is especially true for top-loading chests, where cold air accumulates at the bottom.
List of common problems:
- ❄️ Ice on food: Too low a temperature or infrequent defrosting. Increase the frequency of defrost cycles on the timer.
- 🔊 Noisy operation: Perhaps vibration is transmitted to the housing due to new fasteners. Use anti-vibration pads.
- 💧 Water on the floor: The drainage is clogged or the drip line is full. Check the drainage system.
⚠️ Attention: If you notice that the outside walls of the chest have become warm or hot in certain places, this may indicate that the condenser or heating element is not working properly. Immediately disconnect the device from the network for diagnostics.
Converting a chest freezer into a refrigerator is a cost-effective solution that allows you to get a spacious unit for storing supplies. Subject to technology and electrical safety rules, such a device lasts for years, consuming no more energy than a conventional refrigerator, thanks to the effective thermal insulation of the chest.
Frequently asked questions (FAQ)
Is it possible to remake a chest without installing a heating element, using only a thermostat?
Theoretically, it is possible if manually defrost the chest every 3-4 days. However, without a heating element and a timer, the system will not be automatic. The compressor will be turned off by the thermostat, but the accumulated frost will isolate the evaporator, which will lead to an increase in the operating time of the compressor and an increase in the temperature inside the chamber. Automatic defrosting is required for comfortable operation.
Which thermostat is better to choose: mechanical or electronic?
For remodeling a chest, mechanical thermostats (such as TAM or K-series) are most often recommended because of their reliability, ease of replacement and low cost. Electronic controllers are more accurate, but require more complex installation of sensors and can be sensitive to voltage drops in the network, which is important for summer cottages.
Will a converted chest consume more electricity?
On the contrary. Since the freezer operates in a more gentle temperature mode (+4°C instead of -18°C), the compressor will turn on less often and run for less time. In addition, the excellent thermal insulation of the chests helps to preserve the cold for a long time. Electricity costs can be reduced by 20-30% compared to the deep-freeze mode.
Is it necessary to change the refrigerant or oil in the compressor?
No, interfering with the freon circuit (refilling, changing the oil or refrigerant) during such alterations is absolutely not necessary and is prohibited without a license. Only the electrical control circuit changes. The compressor remains the same, its operating conditions simply change.