Brand refrigerators Biryusa are deservedly considered one of the most reliable units in the post-Soviet space, largely due to their simplicity and time-tested design. The heart of this cooling system is a thermostat, which automatically maintains the set temperature in the chamber by turning the compressor on and off. Understanding exactly how this unit functions allows the owner to independently diagnose many breakdowns without resorting to expensive service.
The principle of operation is based on the physical expansion and contraction of the refrigerant inside a sensitive capillary tube, which responds to changes in temperature in the evaporator. When the air in the chamber heats up above a set threshold, the gas in the tube expands and opens the electrical contacts through the membrane, starting the motor-compressor. After achieving the desired cold, the process proceeds in the reverse order, breaking the power circuit and putting the equipment into standby mode.
Models Biryusa most often use mechanical thermostats, which are characterized by high maintainability and availability of spare parts. However, even reliable mechanics wear out over time, which can lead to incorrect operation of the entire refrigerator. Next, we will analyze in detail the device, types of sensors and algorithms for their interaction with the electrical circuit.
Design and design features of the sensor
Structurally, the thermostat in refrigerators Biryusa is a sealed block consisting of a bellows tube filled with freon or substitute gas, and a group of electrical contacts. The tube, often called a capillary, has a corrugated structure to better perceive temperature fluctuations. One end of this tube is fixed to the evaporator or hangs freely in the air flow, and the other is connected to the switching mechanism.
Inside the body there is a bellows - an accordion-shaped container that lengthens when heated and contracts when cooled. This movement is transmitted to the moving contact, opening or closing the circuit. Some models Biryusa use a system with a single trip contact, while more complex versions may have additional contacts to control the backlight or fan.
⚠️ Attention: The internal structure of the thermostat is sealed. Violation of the integrity of the housing or capillary tube will lead to leakage of the filler gas, after which the device will become completely unsuitable for repair and will require mandatory replacement.
The key adjustment element is the adjustment screw, which is usually accessed through the thermostat knob inside the chamber. By rotating this screw, the user changes the spring tension, thereby shifting the temperature response threshold. This is how the ability to select a mode from “minimum” to “maximum” is realized.
Types of thermostats used in Biryusa models
The manufacturer Biryusa over the years of production has used various modifications of thermostats, which is important to consider when searching for spare parts. The main division occurs according to the type of fastening and the length of the capillary tube, as well as according to the temperature range of operation. For single-chamber models, sensors with a shorter tube and one defrost mode are more often used.
In two-chamber units with a No Frost or drip defrosting system, more complex thermostats are used that can control the temperature in different zones. Some models are equipped with an additional rod for emergency opening of the circuit when the compressor overheats, which is an important safety feature.
Below is a table of the main characteristics of popular series of thermostats installed on equipment of this brand:
| Series / Model | Capillary length | Type contacts | Application |
|---|---|---|---|
| TAM-133 | 1.2 meters | Single contact | Single-chamber refrigerators |
| TAM-112 | 0.75 meters | One contact | Small models |
| K-59 / K-50 | Different (L=1.2-2.5m) | Two contact | Two-chamber models with No Frost |
| T-110 | 0.6 meters | One contact | Chest freezers and cabinets |
When selecting analogue, it is critical to pay attention not only to the markings, but also to the length of the tube. If the new thermostat has a capillary that is too long, it will have to be carefully laid in rings inside the housing, without bending or damaging it.
Symptoms of a malfunctioning thermostat
Diagnostics begins with an analysis of the behavior of the refrigerator. If the compressor runs continuously without turning off for hours, and the food in the main chamber begins to freeze, this is a sure sign that thermostat is stuck in the "on" position or has lost sensitivity. In this case, the gas in the bellows could have evaporated, and the contacts simply do not open.
The opposite situation, when the refrigerator does not turn on at all or operates in very short cycles, also indicates problems with the sensor. In the first case, the circuit is open forever, in the second, the response threshold is so low that the unit does not have time to get cold. This is often accompanied by the absence of a click when turning the regulator knob.
- ❄️ The products in the refrigerator compartment are covered with frost or ice crust, although the knob is set to minimum.
- 🔇 The compressor is silent, only the backlight is on, there are no clicks when turning the knob in both directions.
- 🌡️ The temperature in the chamber does not drop below +10...+15 degrees, the motor turns on rarely and does not work for long.
It is also worth checking the condition of the capillary tube. If it is accidentally bent or displaced from its regular place on the evaporator, the readings will be incorrect. In models with an external handle, sometimes the contacts inside the switch itself oxidize, which requires cleaning or replacing the assembly.
Diagnostics and testing with a multimeter
Before buying a new part, you need to make sure it is faulty. To do this, you will need a regular digital multimeter set to continuity or resistance measurement mode. First of all, you need to completely de-energize the refrigerator by unplugging the plug from the socket.
Next you need to remove the thermostat by first reaching it through the plastic cover or removing the top cover of the case, depending on the model. Biryusa. Having disconnected the wires, we close the multimeter probes to the sensor contacts. At room temperature, a working thermostat should “ring”, indicating the presence of a circuit (resistance is close to zero).
For a more accurate check, you can cool the sensitive tube. To do this, just place it in the freezer for 10-15 minutes or attach an ice pack. Once cooled, the circuit should break and the multimeter will no longer show continuity. If this does not happen, then the mechanism is damaged.
⚠️ Attention: Never check the integrity of the circuit under voltage! All manipulations with the multimeter are carried out only with the device completely disconnected from the network in order to avoid electric shock and failure of the measuring device.
Step-by-step instructions for replacing the thermostat
Replacing the thermostat in the refrigerator Biryusa is a procedure accessible to a person with basic skills in working with tools. The main thing is to act carefully, especially when working with a capillary tube, which is very fragile and easily breaks when bent strongly.
The process begins with dismantling the old unit. After removing the decorative handle and protective panel, unscrew the fastening nuts. Pull the thermostat housing out, carefully straightening the capillary tube. If it is secured with clips to the evaporator, they must be carefully pressed out.
☑️ Algorithm for replacing the thermostat
Installing a new element is done in the reverse order. The capillary tube of the new sensor is laid along the same path as the old one, trying to repeat all the bends. Excessive tension or sharp creases are unacceptable. After connecting the wires and assembling the case, you can turn on the refrigerator.
After turning on, let the unit work for 2-3 hours to reach the operating mode. During this time, do not open the door frequently and do not load the chamber with warm food. listen to the compressor: it should periodically turn on and off with a characteristic click.
Configuration and calibration after installation
After replacing the thermostat, its initial adjustment is often required, since the factory parameters may not perfectly match the operating conditions of your kitchen. The regulator knob should be set to the middle position and wait until the temperature stabilizes.
If the refrigerator turns off too early, without having time to freeze the food, or, conversely, works without stopping, you can adjust the position of the adjusting screw. On many models Biryusa under the thermostat handle there are two small holes for a screwdriver that allow you to change the tension of the springs.
Secrets of adjusting the screws
There are usually two screws inside the mechanism. One is responsible for the temperature range (on/off together), and the second is responsible for the differential (temperature difference). They should be turned a quarter turn, pausing for several hours to check the result.
The optimal temperature in the main chamber is considered to be from +2 to +5 degrees. For precise adjustments, you can use an external thermometer, placing it on the middle shelf. Having achieved the desired indicators, fix the position of the knob so as not to accidentally reset the settings.
Common mistakes during self-repair
One of the most common mistakes is ignoring the length of the capillary tube. Buying a thermostat with a shorter tube will result in it simply not being enough to reach the mounting location on the evaporator. As a result, the sensor will hang in the air and show the temperature not of the freezer, but of the chamber air, which will disrupt the work cycle.
Incorrect installation of the tube is also common. It must be pressed tightly against the surface of the evaporator, sometimes using a special heat-conducting paste or a tight clamp. If the contact is poor, the reaction to temperature changes will be slow, which will lead to a “swing” in temperature and excessive energy consumption.
- 🚫 An attempt to repair the internal mechanism of the thermostat (disassembling the case), which almost always leads to final failure.
- 🚫 Using thermostats from other brands (for example, from washing machines or ovens), which have completely different temperature ranges.
- 🚫 Forgetting to ground the case or check the insulation of the wires before turning it on for the first time after repair.
⚠️ Attention: The characteristics of thermostats may vary slightly depending on the year of manufacture of your model. Biryusa. Always check the markings on the body of the old part with the new one before purchasing, since the appearance of the handles and stems may be identical, but the operating parameters may be different.
FAQ: Frequently Asked Questions
Is it possible to temporarily close the thermostat contacts to make the refrigerator work?
Yes, this is possible for emergency defrosting or short-term storage of food, but this must be done with caution. When the contacts are closed, the refrigerator will operate continuously, which will lead to severe hypothermia and ice freezing. The compressor in this mode wears out and can burn out from overheating, so you cannot keep the refrigerator in this condition for a long time.
Why does the refrigerator not turn off after replacing the thermostat?
Most likely, the new sensor has different temperature thresholds or the capillary tube is installed incorrectly (does not fit tightly to the evaporator). It is also possible that there is not enough freon in the system, and because of this the temperature does not drop to the value at which the new thermostat should work. Diagnostics of the pressure in the system is required.
Which thermostat is better: domestic TAM or imported (Danfoss, Klixon)?
Imported analogues (for example, Danfoss or Ranco) are often considered more durable and accurate, but they are much more expensive. Domestic series THERE are excellent for refrigerators Biryusaas they were originally designed to meet their technical specifications, and they are easier to find on sale in the regions.
Is it necessary defrost the refrigerator before replacing the thermostat?
Yes, complete defrosting is required. Firstly, it is safe for electricians, and secondly, an ice crust on the evaporator can interfere with the correct installation of the capillary tube. In addition, moisture may get inside the electrical contacts during dismantling if there is ice in the chamber.