Refrigerators Pozis are deservedly considered one of the most reliable units in the post-Soviet space, however Even time-tested equipment has failures in the thermoregulation system. If you notice that food in the main chamber has begun to freeze or, conversely, is quickly deteriorating due to insufficient cold, and a “coat” of ice has formed on the back wall, then most likely the problem lies in the temperature sensor. Understanding where the thermostat is located in the Pozis refrigerator is the first and most important step for self-diagnosis of the malfunction.
In most models of this brand, be it classic single-compressor units or more modern versions with the system No Frost, the thermostat serves as the main control element of the cooling cycle. It monitors the temperature inside the chamber and sends a signal to the compressor to turn on or increase. Incorrect operation of this unit can lead to increased energy consumption and premature wear of the motor-compressor, so symptoms of failure cannot be ignored.
In this article we will analyze in detail the design features of various series of refrigerators Pozisso that you can accurately determine the location of the sensor in your model. We will look at the differences between mechanical and electronic control systems, and also provide a step-by-step algorithm for safely replacing a failed element. It is important to understand that although the replacement procedure seems simple, it requires care and compliance with safety precautions when working with electrical appliances.
Design features of thermostats in different Pozis models
Before you start searching for a faulty element, you need to clearly determine what type of temperature control system is installed in your refrigerator. The model range Pozis covers several decades of production, and during this time engineers have used various solutions. In older models, such as series Sviyaga or early Riada, mechanical thermostats with a capillary tube were widely used. These devices are a sealed system filled with gas or liquid that responds to changes in volume when heated or cooled.
Modern refrigerators Pozis, especially those equipped with an electronic display on the door, They use a completely different operating principle. Here the mechanical thermostat is replaced by an electronic temperature sensor, often called a thermistor. It is a small element whose resistance varies depending on the ambient temperature. The signal from such a sensor is sent to the electronic control module, which already makes the decision to start the compressor. You can determine the type of device you have by the presence of a rotary knob with numbers inside the chamber: if there is a knob, you have a mechanic; if there is a screen with degrees on the door, you have an electronic one.
Particular attention should be paid to two-chamber models with separate temperature control. They can have two independent thermostats: one for the refrigerator and one for the freezer. However, in most household models Pozis with one compressor, the thermostat controls only the fridge compartment, and the freezer is cooled according to the residual principle or through a cold distribution system. Accurate identification of the model, since the layout of the sensor and the method for replacing it depend on this.
⚠️ Warning: Before starting any work to find or replace the thermostat, be sure to disconnect the refrigerator from the electrical network. Working with live internal components is strictly prohibited and may result in electric shock or short circuit.
Mechanical thermostats tend to be simpler in design and easier to diagnose visually, but they are less accurate than their electronic counterparts. Electronic sensors, in turn, provide accuracy to a fraction of a degree, but checking them requires using a multimeter to measure resistance. If you are not sure about the type of installed equipment, it is better to refer to the product data sheet or find a sticker with the model on the back wall of the unit.
Location of the mechanical thermostat in the fridge compartment
If your refrigerator Pozis has a mechanical control system installed, then you need to look for the thermostat directly inside the fridge compartment. In the classic version, which is found in 90% of cases, the thermostat is built into the lighting control unit or located next to it. Outwardly, it looks like a plastic knob with numbers from 1 to 5 (or up to 7), by rotating which you set the desired temperature. The thermostat mechanism itself is hidden under this handle.
To access the insides of the device, in most models it is necessary to remove the plastic casing in which the handle is mounted. This casing is usually secured with latches or one or two screws, which may be hidden under decorative caps. After removing the handle and dismantling the plastic panel, a metal or plastic box will open to your view - this is the thermostat housing. A long corrugated tube extends from it, which is called capillary tube. It is this that is the sensitive element that transmits information about temperature.
The capillary tube passes through the inner wall of the refrigerator and ends in a special channel of the evaporator or is attached to the rear wall of the chamber. In some models Pozis, for example, in the series Mir or Biryusa (which often have a similar design), the end of the tube can simply be taped to the evaporator or inserted into the sleeve. It is important not to damage this tube during disassembly, since its depressurization will lead to complete inoperability of the thermostat. If the tube is pinched or has signs of corrosion, the thermostat will not read the temperature correctly.
There are also models where the thermostat is located outside the main chamber, for example, in the foamed part of the case or located at the top, above the door. However, the brand Pozis is characterized by the internal installation in the upper part of the refrigerator compartment. If you removed the handle and plastic trim, but did not see the characteristic block with three or four contacts, inspect the space above - sometimes the block is hidden behind the upper decorative strip.
☑️ Checking the mechanical thermostat
Where to look for an electronic temperature sensor (thermistor)
In modern refrigerators Pozis with electronic control the situation is different. Here you will not find the usual twister inside the camera. Instead, the system relies on data from electronic sensors called thermistors. These items are small devices, often encased in plastic or metal, about the size of a pea or small tablet. Their location depends on the specific model and year of manufacture of the unit.
Most often, the main temperature sensor of the refrigerator compartment is located in the upper part of the rear wall, sometimes hidden behind a decorative plastic panel. In models with the system No Frost sensors can be installed directly in the air duct through which cold air is supplied to the chamber. To get to them, you often need to remove the top cover of the refrigerator or dismantle the back panel inside the chamber. In some cases, the sensor may be built into the control unit, which is located outside, at the top of the refrigerator, but the sensitive element itself is still brought inside.
A separate sensor is provided for the freezer compartment in two-chamber models with electronics. It is usually located in the evaporator area or on the back wall of the freezer. If your refrigerator shows an error on the display (for example, flashing lights), this often indicates that one of the thermistors is faulty. Error codes vary, but temperature sensor problems are often marked with combinations involving the letter "F" (Freezer) or "R" (Refrigerator) and a number.
It is easy to distinguish an electronic sensor from a mechanical one by its appearance: it is not a bulky block with a tube, but a compact element with two thin wires going to the connector. When diagnosing, it is important to check not only the sensor itself, but also the integrity of the wires leading to it, since they can break in places where they are bent or pass through the wall.
Symptoms of a faulty electronic sensor
If the electronic temperature sensor fails, the refrigerator may behave unpredictably. The compressor can operate continuously without turning off, which leads to deep freezing of food in the refrigerator compartment. Or, conversely, the unit may not turn on at all, believing that the temperature has already been reached. Often, when a sensor breaks down, the corresponding failure indicator lights up on the display, and in more complex models, the refrigerator goes into emergency mode with fixed parameters.
Fault diagnosis: how to understand that the thermostat is broken
Before buying a new part and disassembling the refrigerator, you need to make sure that the problem really lies in the thermostat. Symptoms may be similar to a compressor malfunction or freon leak, so careful diagnosis is important. The easiest and most reliable way to test a mechanical thermostat is by visual inspection and the “method of elimination.” If when you turn the knob you do not hear a characteristic click, this does not indicate a breakdown, but is an alarm bell.
More accurate diagnostics can be carried out by closing the contacts of the thermostat. To do this, you need to remove the terminals from the thermostat contacts and connect them to each other (after disconnecting the refrigerator from the network!). If, after turning on the power and closing the contacts, the compressor starts and the refrigerator begins to freeze, then the problem is with the thermostat. If the motor is silent even with the contacts closed, you need to look for the cause in the starting relay, the compressor itself, or the power circuit.
For electronic sensors, diagnostics are carried out using a multimeter in resistance measurement mode (Ohm). The sensor must be removed from the mounting location (or access to its contacts must be provided) and the resistance measured at room temperature. Then you can cool it (for example, by putting it in the freezer for a couple of minutes) and measure the resistance again. The readings must change. If the resistance is zero or infinity (open), the sensor is faulty.
| Symptom | Probable cause | Action |
|---|---|---|
| The refrigerator does not turn on | Open circuit thermostat | Checking the contacts with a multimeter |
| The compressor runs without stopping | Sticking contacts or loss of sensitivity | Replacing the thermostat |
| Severe freezing of the rear walls | Incorrect shutdown of the compressor | Diagnostics of the capillary tube |
| Products in the refrigerator compartment are defrosting | Thermostat does not give a command to turn on | Checking the signal for switching on |
It is also worth paying attention to the condition of the capillary tube of the mechanical thermostat. If it has swelling, traces of oil, or is flattened, this indicates depressurization of the sensitive system. In this case, the thermostat cannot be repaired, only replaced. Oily spots inside the chamber may also indicate a freon leak from the thermostat capillary tube, although this is rare.
Step-by-step instructions for replacing the thermostat
The process of replacing the thermostat in the refrigerator Pozis requires accuracy and a minimum set of tools: a screwdriver (Phillips and flat-nose), pliers and, possibly, side cutters Before starting work, make sure you have purchased a compatible part. Thermostats have different capillary tube lengths and temperature response ranges, so it is advisable to look for a part with the same marking code as the old device.
The first step is always to completely disconnect the unit from the power supply and defrost it. Even if you are replacing a mechanical sensor, ice can make access difficult and create a risk of moisture getting into the electrical contacts. After defrosting, remove the temperature control knob and decorative trim. In some models Pozis to do this you need to pry off the cover with a flat screwdriver, in others you need to unscrew the screw hidden under the plug.
Next you should disconnect the wires from the old thermostat. Important: before disconnecting, take a photo of the connection diagram or sketch which wire goes to which contact approached. The color coding of the wires is not always standard, and a mistake when connecting a new thermostat can lead to a short circuit. If the capillary tube is secured with clips or tape, carefully release it. When removing the old thermostat, try not to pull the tube sharply, so as not to damage the channel in the wall of the refrigerator.
Installing the new thermostat is done in the reverse order. Insert the sensitive tube into the channel until it stops (usually 30-40 cm inside the wall), secure it and connect the wires according to your diagram. Install the plastic casing and handle. After turning on, check the operation of the unit: the compressor should start, and after a while (when the temperature reaches the set one) it should turn off with a characteristic click.
⚠️ Attention: The capillary tube of the new thermostat is very fragile. When installing, avoid bending it at an angle of less than 90 degrees and avoid impacts. Damage to the tube will make the new part unusable.
Common mistakes during self-repair
Do it yourself Repairing refrigerators is a rewarding task, but it is fraught with a number of pitfalls that amateurs often forget about. One of the most common mistakes is ignoring the length of the capillary tube. If you install a thermostat with a shorter tube, it simply will not reach the temperature control zone and the refrigerator will not work correctly. If the tube is too long, it cannot be twisted into tight rings, as this interferes with the circulation of the working fluid inside.
Another common mistake is incorrect installation of the sensing element. In refrigerators Pozis the end of the capillary tube should be in close contact with the evaporator or the chamber wall. If you simply “threw” the tube into the free space of the chamber, the thermostat will respond to the air temperature, which changes more slowly than the evaporator temperature. This will lead to large temperature changes and frequent engine starts.
Also, many people forget about tightness. When replacing the thermostat, a leak may form where the tube exits the refrigerator body. Through this microscopic gap, moist air from the room will penetrate into the insulation, which over time will lead to the formation of an ice coat inside the foam “coat” of the body and swelling of the walls. It is advisable to treat the exit point of the tube with sealant or plasticine.
And, finally, the use of unsuitable analogues. An attempt to install a universal Chinese thermostat without taking into account the temperature range of operation may result in the refrigerator either not turning off at all or not being able to reach the desired temperature. Always check the markings and technical parameters.
What will happen if the wires are mixed up?
Depending on the circuit, mixed up wires can lead to the fact that the light in the refrigerator will be constantly on, even when the door is closed, or the thermostat will work in inverse mode (turn on the cold when it gets cold). In the worst case, a short circuit is possible.
FAQ: Frequently asked questions
Is it possible to repair an old thermostat, or is it only necessary to replace it?
In 99% of cases, repairing a mechanical thermostat is impossible and impractical. This is a sealed device, and violation of its integrity leads to loss of working gas. Electronic sensors also cannot be repaired, since a change in their resistance is a physical process of material degradation. Only a complete replacement guarantees stable operation.
Which thermostat is best to buy for replacement in a Pozis refrigerator?
It is best to look for original spare parts or high-quality analogues from well-known brands, such as Tam, K59, Ranco. Chinese nameless thermostats often have low accuracy and short service life. Pay attention to the length of the capillary tube - it should be no less than that of the original (the excess can be carefully rolled up).
Why did the refrigerator start to turn on frequently after replacing the thermostat?
This may be due to several reasons: the screw under the seal on the new thermostat is not adjusted correctly, the end of the capillary tube is not immersed deep enough in the channel, or the new thermostat has a different temperature response range. Also check the tightness of the door.
Where can you find the thermostat markings in the Pozis refrigerator?
The markings are usually applied to the metal body of the thermostat itself. To see it, you need to remove the adjustment knob and the plastic cover. Look for codes like TAM-133, K-59, 17M, etc. Also, the spare part number can be indicated in the service book or on the diagram, if it has been preserved.
Is it dangerous to leave a refrigerator with a faulty thermostat?
Yes, it is dangerous. If the thermostat is stuck on, the compressor will run continuously, which can lead to overheating, melted wiring, and even a fire. If it doesn't turn on, you'll lose food. Operation of a faulty unit is unacceptable.