Temperature adjustment in old Atlant refrigerators

Owning reliable Belarusian technology often becomes a test of ingenuity, especially when it comes to models released decades ago. Old Atlant refrigerators They are famous for their indestructible design and simplicity, but the lack of electronic control can confuse the modern user accustomed to digital displays. If you notice that the food in the chamber begins to freeze or, conversely, the milk sours faster than expected, then it’s time to intervene in the operation of the mechanical thermostat.

Before grabbing a screwdriver or turning the dials, you need to understand the physical principle of operation of your unit. Unlike modern No Frost systems with precise sensors, in classic models the thermostat, which responds exclusively to the temperature of the evaporator, is responsible for maintaining the climate. thermostat (thermostat), which responds exclusively to the temperature of the evaporator. It is critically important to understand that in older Atlant models there is no separate adjustment for the freezer and refrigeration chambers - changing the position of the handle affects the operation of the entire cooling circuit. This means that you cannot make it colder only in the freezer without affecting the main compartment.

Incorrect settings can lead not only to food spoilage, but also to increased energy consumption or even compressor breakdown due to abnormal operation. In this article we will analyze all the nuances of calibrating mechanical controls, consider the features of various series and answer frequent questions that arise from owners of retro models.

The principle of operation of a mechanical thermostat

The heart of the cooling system in older models, such as Atlant MXM-1700 or Atlant 1800, is a mechanical thermostat. This device is a sealed system filled with gas or liquid that expands when heated and contracts when cooled. Inside the housing there is a bellows, which, when the volume of the working fluid changes, affects the contact group, turning on or off compressor.

The regulator handle that you see on the control panel or inside the chamber does not add cold is artificial. It only sets the temperature threshold at which the contacts will open and the compressor will stop. The higher the number on the scale, the lower the evaporator temperature must drop before the system “decides” that there is enough cold. This puts more stress on the engine, causing it to run longer.

⚠️ Attention: Mechanical thermostats have hysteresis (delayed response). After turning the knob, the temperature in the chamber will not change instantly, but after 2–4 hours of compressor operation. Do not try to turn the regulator every 15 minutes while waiting for the result.

It is important to consider that in two-chamber models with one compressor, the cold is distributed unevenly. The main cold is generated in the freezer, and it enters the refrigerator compartment through channels or simply by convection. Therefore, the setting is always a compromise between the desired temperature in the freezer and the safety of the food in the main chamber.

How does the capillary tube work?

The temperature-sensitive element of the thermostat (capillary tube) is attached to the evaporator or inserted into the chamber. When the evaporator cools, the gas inside the tube compresses, the thermostat membrane bends and opens the electrical contacts. The compressor stops. As soon as the temperature rises, the gas expands, the contacts close, and the cycle repeats.

Deciphering the adjustment scale and the meaning of the numbers

On the control panel of old Atlant refrigerators there is usually a round knob with numbers from 0 to 7 (sometimes from 1 to 5 or MIN/MAX). Many users mistakenly believe that the numbers represent degrees Celsius, but this is completely wrong. The scale points to cooling intensity. Position "0" or "OFF" means complete shutdown of the power supply to the compressor.

The number "1" corresponds to the warmest operating mode. In this position the compressor will switch off as soon as the evaporator temperature reaches relatively high values ​​(eg -5°C). This may be acceptable in the summer in a cool room or when the chamber is not fully loaded, but this mode is not suitable for long-term storage of meat.

On the contrary, the number “7” (or “MAX”) causes the compressor to work almost non-stop or turn off only at very low evaporator temperatures (down to -24°C and below). Constant operation in this mode leads to the formation of a powerful “coat” of ice on the back wall and can cause freezing of food in the main chamber, even if you did not plan it.

• 🌡️ Position 1-2: Economy mode, temperature in the refrigerator is about +7..+9°C, in the freezer about -6..-10°C.
• ❄️ Position 3-4: Optimal mode for everyday use, providing +3..+5°C in the refrigerator compartment.
• 🧊 Position 5-7: Intense freezing or hot summer mode, the temperature in the freezer drops below -18°C, in the refrigerator compartment it can be about 0°C.

Step-by-step instructions: how to set the temperature

Setting process temperature in the refrigerator Atlant requires patience and consistency of actions. You should not expect instant results, since the inertia of the system is great. Before starting manipulations, make sure that the refrigerator is operating normally, the doors are tightly closed, and there is no excessive amount of food inside that impedes air circulation.

First, find the regulator. In most older models (series 17, 18, 27, 28) it is located inside the refrigerator compartment on the right wall or on the ceiling. In older Soviet models (Minsk), the handle may be located outside above the door. Set the knob to the middle position (usually number 3).

After installing the knob in the desired position, you must wait at least a day. Only after this time can measurements be taken. If you set the knob to “3”, and a day later the food in the refrigerator compartment (not at the back wall!) has a temperature above +6°C, turn the knob one notch upward (to “4”). If the vegetables near the back wall freeze, reduce the power to “2”.

In winter, when the apartment is cool (+18°C), the refrigerator may work less often, and the knob will have to be set to higher values. In the summer, at high temperatures in the room, even position “3” may be insufficient, and a switch to “4” or “5” will be required.

The influence of loading and location of products

Even an ideally adjusted thermostat will not save the situation if the operating rules are violated. Heat transfer In old refrigerators, Atlant is built on natural convection. Cold air is heavier than warm air, it sinks, and warm air rises. If you fill the chamber with food to capacity, blocking the ventilation holes (if any) or simply packing the shelves tightly, the cold will not be evenly distributed.

Particular attention should be paid to placing products against the back wall. This is where the evaporator is located - the source of cold. Touching food to the back wall leads to local hypothermia and freezing, even if the thermostat is set correctly. The thermostat reads the temperature of the evaporator, and if a piece of meat is frozen to it, the sensor “thinks” that the entire chamber is already cold and turns off the compressor too early.

The number of products also matters. An empty refrigerator cools down faster, but it also heats up instantly when the door is opened. A full chamber holds the cold better (products act as cold accumulators), but requires more time and energy for initial cooling. If you loaded a lot of warm products at once, temporarily move the control knob to a more powerful value (by 1-2 divisions), and after a day return to normal mode.

Seasonal adjustment and defrosting

Old Atlant refrigerators require manual defrosting. The presence of a layer of ice (“coat”) on the evaporator with a thickness of more than 5 mm critically impairs heat transfer. Ice works as an insulator: the compressor works, it cools, but the cold is not transferred to the products. The thermostat does not sense the real cold and does not turn off the motor, which leads to excessive energy consumption and overheating.

The regularity of defrosting directly affects the temperature settings. If you have just defrosted the refrigerator and loaded it with food, the thermostat may behave unstable in the first hours. During this period, it is better to keep the handle in the middle position. Seasonality also plays a role: in winter, when the heating is weaker or the apartment is cool, the refrigerator may be “lazy” to turn on. In the summer, he has to work to the limit.

⚠️ Attention: Never use a knife, ice pick or hot air hair dryer to speed up defrosting. Mechanical damage to the evaporator (tubes inside the chamber) will lead to freon leakage and costly repairs. Defrost only naturally by unplugging the appliance.

After completely defrosting and drying the chamber, let the refrigerator run empty for 1-2 hours. During this time, the temperature fields stabilize, and only after this can you load products and assess the need to adjust the thermostat.

Diagnostics of thermostat malfunctions

Sometimes it happens that the regulator knob is set correctly, the products are placed according to the rules, but the temperature still “floats”. This may indicate a malfunction thermostat or a refrigerant leak. If the compressor works non-stop for days, but there is no cold, most likely the problem is not in the settings, but in the technical part (freon leak, capillary clogged).

If the compressor does not turn on at all, even when the knob is turned to the maximum, and the chamber is warm, the contacts may be stuck thermostat or the capillary tube has broken. In older Atlant models, a situation often occurs when the thermostat “sticks” in the “off” position. Lightly tapping the regulator body sometimes helps to restore contact, but this is a temporary solution.

Incorrect operation in different positions of the handle can also be a sign of a malfunction. If the refrigerator behaves the same at number “1” and at number “7” (for example, it freezes very much or does not freeze at all), this is a sure sign that the mechanics of the thermostat are broken and need to be replaced. A new thermostat for Atlant is inexpensive, and its installation can be done by a technician with basic skills.

Frequently asked questions (FAQ)

Why do vegetables freeze in the Atlant refrigerator, although the knob is set to minimum?

This is a common problem with older models. Even at minimum, the evaporator temperature can be below zero. Try storing vegetables in special containers or bottom drawers, away from the back wall. Also check the door seal: if it lets warm air through, the compressor will work more often, enhancing the effect.

Is it possible to replace a mechanical thermostat with an electronic one?

Theoretically, it is possible by installing an external electronic thermostat with a remote sensor, which will break the power supply circuit of the refrigerator. However, this requires tampering with the electrical circuit and drilling holes for the sensor. For old Atlas, this is rarely justified economically.

What is the normal temperature in the freezer of an old Atlant?

For models with mechanical control, the norm is considered to be a temperature from -6°C to -18°C, depending on the position of the handle. If the freezer is small (shelf at the top), it is not intended for long-term storage of meat, only for short-term storage (up to 3 days).

The refrigerator does not turn off, although it is very cold inside. What to do?

Most likely, the thermostat has failed (the contacts do not open) or a freon leak has occurred (the compressor drives the remaining gas, but there is little cold, although the evaporator may be cold). In the first case, you need to replace the thermostat, in the second - refilling and searching for leaks.