Stable operation of the cooling system directly depends on the serviceability of the control elements, the main one of which is the thermostat. Many owners of household appliances are faced with a situation where food in one chamber freezes, and in another begins to deteriorate due to insufficient cold. It is thermostat responsible for maintaining a given temperature regime, opening and closing the electrical circuit of the compressor.
In refrigerators Atlant this unit plays the role of a kind of “brain” that constantly analyzes the conditions inside the chambers. If you notice that the unit works without interruptions or, conversely, does not turn on for too long, the problem often lies in incorrect sensor readings. Understanding the principle of its operation will help you quickly diagnose a breakdown and avoid spoilage of food supplies.
Let's take a closer look at how this mechanism works, what functions it performs and why its correct setting is critical for the energy efficiency of your refrigerator. In this article, we will look at the technical nuances that will help you distinguish a malfunction of the thermostat from other system malfunctions.
The basic principle of operation of the thermostat
The key task of the thermostat is to automatically turn the compressor on and off depending on the temperature inside the refrigerator or freezer. Inside the device is a sealed bellows tube filled with a sensitive gas or liquid that responds to thermal expansion and contraction. When the air in the chamber heats up above the set norm, the gas in the tube expands, presses on the membrane and closes the contacts, starting the compressor.
As soon as the temperature reaches a predetermined minimum, the process proceeds in the reverse order: the gas is compressed, the membrane is unbent, and the electrical circuit is opened. Refrigerators Atlant often use mechanical regulators, where turning the knob changes the tension of the spring, which allows the user to independently set the response threshold. This is a simple but reliable mechanism that does not require complex electronics.
⚠️ Attention: In some modern models Atlant electronic thermostats can be installed. They work on a similar principle, but the signal is supplied not mechanically, but through a control board. Diagnostics of such devices requires a multimeter and special knowledge.
It is important to understand that the thermostat tube (capillary) must be tightly fixed to the evaporator or in a special groove. If the fastening is loose, the sensor will read the air temperature, and not the evaporator temperature, which will lead to incorrect operation of the entire unit. Heat transfer in this case, it is disrupted and the compressor operating cycles are disrupted.
How does a gas-filled tube work?
Inside the capillary tube there is freon or freon. As the temperature drops, the gas pressure drops and the bellows contracts, opening the contacts. When heated, the pressure increases, pushing the membrane to close the circuit. This is a physical process that does not depend on electricity, which ensures high reliability.
Thermostat functions in different chambers
In two-chamber refrigerators Atlant a system is often used where one thermostat controls the operation of the compressor, but is set to the parameters of the refrigeration chamber. The freezer in such models operates on the residual principle: while it is cold in the upper compartment, the compressor may not turn on, even if the temperature below has already begun to rise. However, there are models with separate circuits or a system No Frostwhere the thermostat can control defrosting.
The main function of the regulator is to prevent defrosting of food. If the thermostat is faulty and does not give the command to turn on the motor, the temperature in the chamber will begin to rise. In the refrigerator, this will lead to souring of the milk, and in the freezer, it will lead to the melting of ice and loss of properties of frozen foods. Conversely, if the contacts stick in the closed state, the compressor will work continuously.
Continuous operation of the motor is dangerous because everything in the refrigerator compartment will freeze, turning vegetables into ice blocks, and the compressor, without rest, can burn out from overheating. The thermostat here acts as the main defender of the equipment resource, providing the necessary pauses for cooling the motor windings and stabilizing the pressure in the system.
- ❄️ Controls the upper and lower temperature thresholds for turning the motor on and off.
- 🛡️ Protects the compressor from working non-stop, preventing overheating.
- 🌡️ Provides a stable microclimate for long-term storage of different types of products.
It is worth noting that in models with two compressors (separately for the freezer and refrigeration compartment) two independent thermostats are installed. In this case, the breakdown of one sensor does not affect the operation of the second circuit, which simplifies the localization of the fault. You will immediately notice that one chamber is working normally, while the other is out of order.
Symptoms of a malfunctioning thermostat
You can determine that the thermostat is out of order by a number of characteristic signs that appear in the behavior of the refrigerator. The most obvious symptom is that the compressor either does not turn on at all or works non-stop. In the first case, the cells are warm, the lights are on, but there is no cold. In the second, the unit hums constantly, and excessive ice forms inside or all the products are covered with frost.
Another sign is the motor turning on too often. If the refrigerator Atlant began to “clock” (turn on and off every 2-3 minutes), this indicates that the thermostat does not maintain the range. The membrane has become too sensitive or has lost its elasticity, causing the slightest change in temperature to cause a reaction. This leads to rapid wear of the start relay and the compressor itself.
Sometimes there is a situation when the refrigerator turns off by itself and does not turn on for a long time until you tap on the regulator knob or move it. This indicates burning of the contacts inside the thermostat or a violation of the mechanical connection of the rod. In such cases, operation of the equipment becomes impossible without replacing the unit.
| Symptom | Probable cause in the thermostat | Consequences |
|---|---|---|
| The compressor does not start | Open circuit or oxidation contacts | Defrosting of products, spoilage of supplies |
| Work without stopping | Sticking of contacts or gas leakage from the bellows | Freezing of products, wear of the motor, high electricity consumption |
| Frequent switching on (clocking) | Faulty spring calibration | Failure of the starting relay, overheating of the wiring |
| Temperature jumps | Loose fit of the capillary tube | Unstable storage, condensation inside the chambers |
It is important not to confuse a thermostat breakdown with a freon leak or a compressor malfunction. If there is a freon leak, the compressor can also work constantly, but the evaporator itself will be only partially cold or not cold at all. The thermostat has nothing to do with it, it simply tries to compensate for the lack of cold, constantly requiring the motor to work.
Diagnostics and checking the regulator
Before buying a new part, you need to make sure that the problem is in the thermostat. The simplest method of primary diagnosis is visual inspection and the “folk” method of contact closure. To do this, disconnect the refrigerator from the network, remove the regulator knob and the protective casing to gain access to the thermostat terminals.
Carefully remove the two terminals suitable for the thermostat and connect them together with a piece of wire, having previously stripped the ends. If, after connecting to the network, the compressor started working and the refrigerator began to freeze, it means that the circuit is working properly, and the thermostat does not give a signal to start. This confirms the need to replace the regulator.
⚠️ Attention: Testing with closed contacts can only be carried out briefly, under constant supervision. Do not leave the refrigerator in this state overnight, as it will freeze indefinitely until you open the circuit manually.
A more accurate method is to use a multimeter in dial mode. At room temperature, the contacts of most thermostats Atlant must be closed (the device beeps). If you place the sensing tube in the cold (for example, in the freezer for 10-15 minutes), the circuit should break. The absence of changes in the device readings indicates a malfunction of the part.
☑️ Checking the thermostat with a multimeter
It is also worth inspecting itself capillary tube for mechanical damage, dents or signs of corrosion. If the tube is pinched or deformed, the pressure inside the bellows will change incorrectly, resulting in false readings. In such cases, even a working electrical part will not save the situation.
Rules for setting and adjusting the temperature
Correct setting of the thermostat is the key to long service life of products and saving energy. In refrigerators Atlant adjustment is usually carried out by turning the knob with divisions from 1 to 7 (or Min to Max). Many users mistakenly believe that the number indicates degrees, but in fact this is the level of cooling power.
The average value (usually 3 or 4) is considered the optimal position for everyday use. In this mode, the refrigerator is able to maintain a temperature of about +4...+5°C in the refrigerator compartment and -18°C in the freezer, taking the necessary breaks in operation. Setting it to maximum (7 or Max) makes the compressor work almost non-stop.
Seasonality also affects the settings. In summer, when the room is hot, you can slightly increase the power, but not to the maximum. In winter, if the refrigerator is in an unheated room, the use of the device may be completely prohibited by the manufacturer, since the oil in the compressor thickens, and the thermostat may not turn on the motor due to the low ambient temperature.
If you have changed the settings, give the refrigerator 5-6 hours to stabilize the temperature. You shouldn't turn the knob every half hour trying to catch the ideal. The thermostat is an inertial device, and it needs time to react to changes and adjust the operation of the system.
Replacing the thermostat: what to look for
If diagnostics confirm a malfunction, the thermostat must be replaced. For refrigerators Atlant it is important to choose an analogue with identical parameters, since the length of the capillary tube and the temperature range of operation may differ for different models. Using an unsuitable part will lead to incorrect operation or complete failure of the system.
When purchasing, pay attention to the markings. Often a code is printed on the body of the part, which can be used to find an exact analogue. It is also important to consider the number of contacts (2 or 3) and the presence of grounding. The third contact is usually responsible for indicating the operation of the compressor (light), and if your model does not provide it, it can be ignored.
Installation of a new part requires care, especially when laying the capillary tube. It should not be twisted, bent at an acute angle or pulled too hard. The tube must be pressed tightly to the evaporator in the same place where the old one was fixed, otherwise the thermostat will “lie” about the temperature inside the chamber.
- 🔧 Select a thermostat strictly according to the catalog number or full marking of the old part.
- 🧊 Monitor the integrity of the capillary tube during installation - any microcrack will disable the device.
- 🔌 Connect the terminals correctly, remembering or photographing the connection diagram before disassembling.
After replacement, be sure to carry out a test run. Load the chambers with food at least halfway (an empty refrigerator does not work correctly) and monitor the power cycles throughout the day. If the operating mode is stable and the temperature is normal, the repair can be considered successful.
Frequently asked questions (FAQ)
Is it possible to temporarily operate a refrigerator with a faulty thermostat?
Theoretically, it is possible if you manually turn the unit on and off using a timer, but this is extremely inconvenient and risky. Constant monitoring is necessary to prevent defrosting or deep freezing. It is better to replace the part.
Why does the refrigerator freeze less easily after replacing the thermostat?
Perhaps a thermostat with a different temperature range is installed (for example, for a warmer climate) or the capillary tube does not fit well to the evaporator. It is also worth checking the amount of freon in the system.
Where is the thermostat located in the Atlant refrigerator?
In most models, it is located inside the refrigerator compartment, under a plastic cover, next to the temperature control knob. The capillary tube goes into the foamed circuit or is attached to the evaporator.
How long does a thermostat in a refrigerator last?
The average service life of a high-quality thermostat is 7-10 years. However, frequent power surges and temperature fluctuations can shorten this period. Mechanical wear of contacts is a natural process.