The situation when the refrigerator Biryusa stops turning off or, conversely, does not want to start the compressor, often confuses the owner. In most cases, the reason for this behavior is the failure of the thermostat - the device responsible for maintaining the set temperature inside the chambers. It is this small device that controls the operation of the motor, closing and opening the electrical circuit depending on the sensor readings.
Before calling a technician or buying a new part, it makes sense to conduct independent diagnostics. This will save your budget and understand whether the problem really lies in the temperature controller or whether the malfunction is of a more serious nature, affecting itself compressor or the defrost system. Correct diagnosis requires care and compliance with safety precautions when working with electrical appliances.
In this article we will analyze all available testing methods, from visual inspection to the use of measuring instruments. You will learn how to distinguish a regulator failure from other defects and whether it is worth replacing the part yourself. Understanding the principles of operation thermostat will help you quickly bring your equipment back to life.
Principle of operation and signs of thermostat malfunction
Thermostat in refrigerators Biryusa works on a simple principle: it reacts to changes in the temperature of the evaporator or air in the chamber. Inside the device there is a bellows tube filled with gas or liquid, which contracts when cooled and expands when heated. This mechanical movement is transmitted to the contacts, closing the compressor power circuit.
When a part fails, the refrigerator begins to behave inappropriately. The most striking sign is the continuous operation of the motor without stopping, which leads to freezing of food and the formation of a thick ice crust on the walls. In other cases, the opposite picture is observed: the unit is silent, the temperature inside rises, and the food begins to deteriorate.
- 🧊 The compressor works around the clock, without turning off even at the minimum settings.
- 🔥 The refrigerator does not turn on at all, although the light inside is on.
- 🌡️ The temperature in the chambers does not correspond to the set position of the regulator knob.
- 💧 The appearance of a large amount of condensation or water under the unit due to frequent defrost cycles.
It is important to understand that similar symptoms can be observed with a freon leak or a faulty start relay. However, if the engine hums and tries to start, but then clicks and stalls, the problem most likely is not with the thermostat. If the motor simply does not receive a start command or does not see a stop signal, this is the responsibility of the thermostat thermostat.
⚠️ Attention: If you notice that the refrigerator body is very hot and the motor has been running without interruption for more than 12 hours, immediately disconnect the device from the network. Long-term operation in this mode can lead to thermal breakdown of the motor windings and expensive repairs.
ℹ️ Information: The design of thermostats may differ depending on the year of manufacture of the model Biryusa. Older models use mechanical devices with a capillary tube, while new ones use electronic sensors, the testing principle of which may require a different approach.
Preparation for diagnostics: dismantling and visual inspection
Before starting any work on checking electrical circuits, it is necessary to ensure safe access to the unit. First of all, the refrigerator Biryusa needs to be completely de-energized. Unplug the power cord from the outlet and move the unit away from the wall to have free access to the back and internal chambers.
The thermostat is usually located inside the refrigerator compartment, often hidden behind a plastic panel or directly in the body of the temperature control knob. In some models, access to it is through the top of the case or the rear wall from the outside. You will need to remove the decorative trims using a screwdriver and possibly a knife to carefully pry up the plastic latches.
After removing the control unit, perform a thorough visual inspection. Look for signs of oxidation on the contacts, melting of the plastic, or damage to the integrity of the wire insulation. The capillary tube should not have kinks, cracks or signs of corrosion. Any mechanical damage to the thermostat housing indicates the need to replace it, even if the electrical part is intact.
When dismantling, it is recommended to photograph the wiring diagram. Color coding may vary and incorrect assembly will result in a short circuit. Write down which wire is connected where, or make a simple diagram on paper. This will greatly simplify reassembly after testing.
⚠️ Attention: The thermostat capillary tube is very thin and fragile. If handled carelessly, it can easily be damaged, which will lead to leakage of the working substance and complete failure of the part. Do not bend the tube at sharp angles.
☑️ Preparation for diagnostics
Contact closure method: testing without instruments
The easiest way to check the functionality of the thermostat at home is the exclusion method, which does not require special tools. The essence of the method is to force the compressor to start by closing the contacts that go from the thermostat to the motor. If the refrigerator starts when shorted, then the problem is most likely in the regulator.
To implement this method, you need to find two main wires suitable for the thermostat. Usually these are wires coming from the mains and going to the compressor. In most schemes they have the same color or markings. Carefully strip the insulation from the ends of the wires or use a jumper with clamps.
Connect the two wires together. If the thermostat was faulty and did not close the circuit, then with an artificial connection the compressor should work. Starting the engine confirms that the starting relay and the engine itself are working properly, and the thermostat does not really give a signal to turn on.
However, this method has its limitations. It is good for checking the switching circuit, but does not fully guarantee the serviceability of the shutdown mechanism. If the refrigerator turns on, do not leave it running in this mode for a long time. Your task is only to record the fact of startup, after which the circuit needs to be opened.
What to do if the refrigerator does not turn on after a short circuit?
If the compressor is silent when the contacts are closed, this does not always mean that the thermostat is working. The problem may be deeper: the start relay is faulty, the compressor itself has burned out, or the wiring is broken. In this case, checking the thermostat fades into the background, and diagnostics of the motor group is required.
After checking, be sure to insulate the wires and return the circuit to its original state. Long-term operation of the refrigerator bypassing the thermostat is unacceptable, as this will lead to defrosting or, conversely, deep freezing of the entire contents.
Diagnostics with a multimeter: checking the resistance
A more accurate and professional method is checking thermostat using a multimeter (tester). This device allows you to measure the resistance of a circuit and accurately determine whether current is passing through the contacts at various positions of the control knob. To work, switch the multimeter to continuity mode or resistance measurement (Ohm).
First check the terminals (contacts) of the thermostat in the "off" position. If your model has a separate shut-off position (usually extreme counterclockwise or a special point), the resistance should be infinite (one on the screen). If the device shows zero or makes a squeaking noise, the contacts are stuck and the part requires replacement.
Then move the knob to the maximum cooling capacity position. In this state, the contacts should be closed and the multimeter should show a resistance close to zero. If the device shows a break (infinity), it means that the internal mechanism does not work and the circuit does not close.
| Handle position | Expected reading | Diagnosis for deviation |
|---|---|---|
| Off (0 / Off) | Infinity (∞) | Contact sticking, risk of spontaneous start-up |
| Maximum cold | 0 Ohm (Sound) | Open circuit, compressor will not start |
| Middle position | 0 Ohm (Sound) | Faulty bellows or bimetallic plate |
| Capillary heating | Infinity (∞) | No contacts open, the refrigerator does not turn off |
To check the circuit opens, you can heat the capillary tube. Hold the thermostat in your hand (body temperature may be sufficient) or gently heat the tube with a hairdryer on the lowest setting. When heated, the contacts should blur, and the multimeter should detect an open circuit. If this does not happen, the mechanism is defective.
Checking the tightness of the bellows tube
One of the hidden reasons for the malfunction of the thermostat is the depressurization of the bellows tube. There is a refrigerant inside it that reacts to temperature. If a microcrack appears in the tube, the gas evaporates and the device stops “feeling” the cold, stopping turning on the compressor.
Checking the tightness visually is difficult, but you can try to detect a leak. Dip the end of the capillary tube (if it is disconnected from the evaporator) into a container of water and slightly heat the tube itself. The appearance of air bubbles will indicate the location of depressurization. However, this method only works if there is still gas left in the tube.
Most often, an indirect sign indicates a loss of tightness: the tube is cold to the touch, but the compressor does not turn on, although the multimeter shows the serviceability of the electrical contacts. In this case, the thermostat formally “rings”, but is functionally dead, since it does not respond to changes in the ambient temperature.
It is almost impossible to restore the tightness and fill the tube with refrigerant at home. Special equipment is required for vacuuming and filling. Therefore, if this diagnosis is confirmed, thermostat can only be completely replaced with a new analogue.
⚠️ Attention: Do not try to open the thermostat housing or solder the capillary tube yourself. There are toxic substances inside, and a violation of the factory calibration will make the device unsuitable for accurate operation.
Replacing the thermostat: step-by-step algorithm
If the diagnostics confirm the malfunction, the only solution is to replace the part. For refrigerators Biryusa it is important to choose an exact analogue, since the length of the capillary tube and temperature range may differ. The part number is usually indicated on the body of the old thermostat.
The replacement process begins with the purchase of a new element. Make sure the length of the capillary tube is the same as the original. If the new tube is longer, you can carefully roll it into a ring and secure it inside the housing, but do not cut it under any circumstances. Shortening will disrupt the volume of the working fluid and disrupt the calibration.
Install a new thermostat in place of the old one, securing it with fasteners. Connect the wires strictly according to the diagram or photograph made earlier. Pay special attention to grounding if it is provided for in the design. Carefully insert the capillary tube into the hole and secure it to the evaporator as it was installed earlier (usually it is pressed with a metal bar).
After assembly, turn on the refrigerator. The initial launch may take some time. Allow the unit to run for several hours without loading food to ensure proper on/off cycles. Check whether it reaches the desired temperature and turns off on time.
Frequently asked questions (FAQ)
Is it possible to temporarily operate a refrigerator with a faulty one? thermostat?
Theoretically, it is possible if you use an external socket timer that will cyclically turn the power on and off (for example, 30 minutes of operation, 30 minutes of pause). However, this is a temporary and risky measure, since it is difficult to choose the ideal mode, and the products may spoil or freeze.
Why does the new thermostat not fit the length of the tube?
The length of the capillary tube is a critical parameter. If the tube is too short, it will not reach the desired area of the evaporator and the sensor will show the wrong temperature. If it is too long, it can be carefully laid in rings, but cannot be shortened. When purchasing, always check the length with the original.
How often do you need to change the thermostat in the Biryusa refrigerator?
The service life of the thermostat depends on the intensity of use. On average, mechanical thermostats last 5-7 years. Frequent power surges and sudden temperature changes can shorten this period. No planned replacement is required, only after a breakdown.
Does the temperature in the room affect the operation of the thermostat?
Yes, it does. If the room is too cold (below +10...+15°C), the thermostat may “think” that the refrigerator is already cold enough and does not turn on the compressor. Most household models Biryusa are designed to work in climate class SN-T (from +10 to +43 degrees).