How to check the thermostat of a Biryusa refrigerator: step-by-step instructions

Refrigerators Biryusa are deservedly considered one of the most reliable units in the post-Soviet space, but even time-tested equipment has failures. Most often, owners are faced with a situation where the compressor stops turning on or, conversely, works without interruption, not turning off even when the chambers are very cool. In 80% of such cases, the culprit of the malfunction is thermoregulator, which ceases to respond correctly to changes in temperature inside the refrigerator compartment.

Independent diagnosis of this unit is a task quite feasible for a person who knows how to keep hands multimeter and screwdriver. You don’t have to call a technician right away if you suspect this particular element, because checking it takes a little time and does not require complex special tools. However, it is important to understand that thermostat is a sensitive device, and its replacement or adjustment requires care so as not to damage the capillary tube or electrical contacts.

In this article we will analyze in detail the algorithm of actions that will help you determine whether the problem really lies in the temperature sensor. We will look at symptoms, diagnostic methods using a multimeter, and even testing methods without instruments, using only available tools. Accurate diagnostics will allow you to save money on calling a specialist if you decide to replace it yourself.

Main signs of a malfunctioning thermostat

Before you start disassembling the unit, you need to make sure that the symptoms point specifically to the thermostat, and not to a freon leak or a compressor malfunction. There are several characteristic signs that most likely indicate a breakdown of this particular control element. Ignoring these signals can lead to food spoilage or failure of more expensive refrigerator components.

The first and most obvious symptom is a violation of the temperature regime. If you notice that the food in the refrigerator compartment has begun to freeze, and a thick coat of ice has formed on the back wall, although the regulator is set to minimum, this is an alarming signal. In such a situation thermostat contacts they may be “stuck” in a closed state, due to which the compressor operates continuously without receiving a command to stop.

⚠️ Attention: Prolonged operation of the compressor without shutting down leads to its overheating and eventual combustion of the windings. If you notice that the refrigerator is constantly humming and does not turn off for hours, immediately disconnect it from the network for diagnostics.

The opposite situation is also possible: the compressor does not start at all, and the chamber is at room temperature. At the same time, the light bulb lights up, which indicates the presence of voltage in the network. This means that the circuit is broken and does not send a signal to start the engine. Sometimes in such cases a quiet click is heard, but no startup occurs, which may indicate oxidation of the contacts inside the sensor. thermostat does not give a signal to start the engine. Sometimes in such cases a quiet click is heard, but startup does not occur, which may indicate oxidation of the contacts inside the sensor.

• 🧊 The food in the refrigerator compartment freezes, although the regulator is turned to minimum.
• 🔇 The compressor is silent, the refrigerator does not cool, but there is light inside.
• 🔊 Frequent turning on and off of the motor (short operating cycle).
• 💧 The appearance of puddles under the refrigerator due to constant thawing of ice.

It is worth noting that similar symptoms can be observed with other malfunctions, for example, with a refrigerant leak or breakdown of the start relay. That is why visual inspection and subsequent check with a multimeter are mandatory steps before purchasing a new spare part. Do not rush to throw away the old sensor until you are completely convinced that it is not working.

Where is the thermostat located in Biryusa models

The location of the thermostat in refrigerators Biryusa depends on the year of manufacture of the model and the type of control (mechanical or electronic). In most classic two-compartment models with mechanical control, the sensor is located inside the refrigerator compartment. To gain access to it, you need to remove the plastic cover that hides the temperature control knob.

Usually this attachment is simply removed by hand, after which the rod going deep into the body becomes visible. It thermostat housing can be hidden behind a decorative panel or located directly under the handle. In some models, especially older series, to access the terminal block you will need to partially dismantle the internal shelf or remove the lampshade, since the sensor is often mounted next to them.

The situation changes if you have a modern model with a system No Frost or electronic control. In such units there may be no mechanical “twist” inside the chamber at all. Temperature sensors (thermistors) are built into the air ducts or mounted on the evaporator, and checking them requires disassembling the rear wall of the chamber or removing the protective panels of the freezer compartment. Here we are talking about more complex diagnostics, where the accuracy of resistance readings is important.

It is important to understand the design of your device so as not to damage the fragile plastic at low temperatures. If you cannot find the sensor, refer to the instructions for the specific model Biryusa, where the location of the nodes is usually indicated on the diagrams. In models with one chamber, access is often achieved by removing the top cover of the refrigerator body.

Removing the thermostat for inspection

For high-quality diagnostics, it is best to remove the thermostat from the refrigerator, although in some cases the initial check can be carried out on site. However, to work with a multimeter and conduct tests with water, access to the contacts must be free and safe. Before starting any work be sure to turn off the refrigerator from the electrical network, remove the plug from the socket.

The dismantling process begins by removing the regulator handle. If it's tight, you can gently pry it open with a flathead screwdriver, but be careful not to break the plastic stem. After removing the handle, unscrew the fastening screw, if any, and remove the decorative trim. Next, you will have access to the thermostat housing, which is usually mounted on a bracket or inserted into a special hole in the chamber wall.

The next step is to disconnect the electrical wires. They fit into the sensor terminals and can be secured with screws or simply pressed on tightly. Remember or take a photo of which wire went to which terminal, as incorrectly connecting the new sensor can lead to a short circuit. The capillary tube, which goes deep into the wall or is attached to the evaporator, must be released with extreme caution.

If the capillary tube is attached to the evaporator with brackets, they need to be carefully unbent. In some models Biryusa the tube is simply inserted into the hole and secured with sealant or foam - in this case it must be very delicately pulled out, trying not to damage the thin copper tube, which contains a sensitive liquid or gas. Damage to the tube will make the thermostat unusable.

Checking the thermostat with a multimeter

The most reliable way to determine the functionality of the thermostat is to check its electrical resistance using a multimeter. To do this, switch the device to resistance measurement mode (Ohm) or “continuity” mode. If your multimeter has an audible short circuit indication mode, this will greatly simplify the task. You will need to check the contacts that go to the thermostat.

In normal condition at room temperature, the contacts of most refrigerator thermostats Biryusa must be closed. Place the multimeter probes on the two main terminals (usually they are labeled 3 and 4, or are simply the main terminals). If the device shows zero or emits a beep, the circuit is closed, which indicates that the contacts are working properly in this temperature regime. If the resistance is infinitely high (one on the screen), then there is a break inside.

However, just ringing at room temperature is not enough. The essence of the thermostat is to open the circuit when a certain low temperature is reached. To check this, place the sensitive part of the sensor (capillary tube with flask) in a container with water and ice, cool it to 0..-5 degrees. After cooling, the contacts should open and the multimeter should show no conductivity.

If after cooling the contacts do not open, it means sensor mechanism it is broken and it does not respond to cold. Such a thermostat will keep the compressor on constantly, which will lead to freezing of food. In this case, the part must be replaced with a similar one.

Diagnostic method without a multimeter

What to do if there is no tester at hand and the refrigerator does not work? There is a popular, but quite effective method of verification based on the principle of exclusion. It does not give a 100% guarantee, but it allows you to determine with a high probability whether it is worth looking for a new spare part. This method is suitable for initial diagnostics at home.

The essence of the method is to close the thermostat contacts directly, bypassing the sensor itself. To do this, you need to remove the wires from the thermostat terminals and connect them to each other (observing caution and safety precautions!). If after making this connection the refrigerator compressor starts and starts working normally, then the problem is almost certainly in the thermostat. The engine is working, so is the relay, and the control circuit is opened precisely by the sensor.

⚠️ Attention: An experiment with direct short circuit of wires can only be carried out briefly and under constant supervision! Do not leave the refrigerator turned on in this way unattended, as it will work without stopping until you open the circuit manually.

Another indirect method is visual inspection. Remove the thermostat and carefully inspect its housing. If you notice traces of soot, melted plastic, or smell a burning smell, this is a clear sign that there is a short circuit or overheating of the contacts inside. It is also worth checking the integrity of the capillary tube: if it is flattened or damaged, the tightness of the system is broken and the sensor will not work.

If the compressor is silent after a direct short circuit of the wires, the problem may be deeper: in the start relay, the motor itself, or the wiring. In this case, simply replacing the thermostat will not help, and more serious repairs will be required. However, in most cases, when the light in the refrigerator is on but there is no cold, the sensor is the culprit.

Replacing and setting up a new thermostat

If diagnostics confirm a malfunction, the only solution is replacement. When purchasing a new thermostat for Turks pay attention not only to the appearance, but also to the markings. It is important that the response temperature range matches the original. The length of the capillary tube is also critically important: if it is too short, you will not be able to correctly place the sensor in the chamber, and if it is too long, you will have to carefully roll it up without bending it.

Installation is carried out in the reverse order of removal. Insert the capillary tube into the hole until it stops, secure it with a staple or sealant as it was originally. Connect the wires strictly according to the memorized or photographed diagram. After assembly, do not rush to turn on the refrigerator immediately - let it stand for 2-3 hours, especially if you performed tests with water or changed the refrigerant (although when replacing only the thermostat, this is less critical, but useful for stabilization).

After switching on, adjustments will be required. Set the control knob to the middle position (usually number 3 or 4). Let the refrigerator run for a few hours and check the temperature inside the compartment using a thermometer. If the temperature does not correspond to the desired values, it may be necessary to adjust the screw on the thermostat itself, which is often hidden under a seal or protective cover. You need to turn it very carefully, literally half a turn.

If you are faced with a non-standard design of the unit, it is better to check the manufacturer’s technical documentation or consult an authorized service center to avoid mistakes when installation.

Frequently asked questions (FAQ)