Refrigerators Pozis have proven themselves to be reliable units that can operate for many years, but even the highest quality equipment is subject to wear. One of the most common malfunctions that owners encounter is the failure of the thermostat, which is responsible for maintaining the set temperature inside the chambers. Understanding where the thermostat is located in your model is the first and most important step to self-repair, which will save significant money on calling a technician.
The location of this unit directly depends on the design features of the specific series and year of manufacture of the device. In some models, access to the regulator opens immediately after removing the plastic plug inside the fridge compartment, while in others it is necessary to completely dismantle the top cover of the housing. Thermoregulator is a key element of the control system, and errors in its search can lead to damage to the wiring or plastic fasteners.
In this article We will analyze in detail the search algorithm, types of location depending on the model, and also provide tips on safe removal of the part. Correct diagnostics will allow you to determine whether the problem lies in this particular component or the reason lies deeper, for example, in compressor or the defrost system.
Design features of thermostats using the Pozis technique
Before you start searching, You need to understand exactly what type of device you are dealing with. Refrigerators Pozis, especially in classic models with mechanical control, use capillary thermostats. The principle of their operation is based on the expansion and compression of a special gas or liquid inside a sealed tube, which is called capillary. It is this tube that most often becomes a vulnerable point if handled carelessly.
The regulator body itself is usually made of plastic and has several contacts for connecting an electrical circuit, as well as a seat for the temperature control knob. In more modern models equipped with electronic control, the function of a mechanical thermostat is performed by temperature sensor (thermistor), which looks like a small plastic element with two wires. The location of the electronic sensor is often different from its mechanical counterpart and may be closer to the evaporator or in the air duct.
⚠️ Attention: Before any manipulations with the electrical components of the refrigerator, be sure to disconnect the device from the network. Working with live parts under voltage is deadly.
It is important to consider that the length of the capillary tube is not random. It is laid around the perimeter of the evaporator or built into the chamber wall to accurately read temperature changes. If during your search thermostat you find that the tube is damaged or has traces of bending, this means that the unit requires complete replacement, since the sealed system cannot be repaired.
What is the difference between a mechanical thermostat and an electronic one?
The mechanical thermostat has an adjustment knob with numbers and makes a characteristic click when switching. The electronic sensor (thermistor) has no moving parts, is a resistor that changes resistance depending on temperature, and is controlled via an electronic board.
Localization in models with a top housing cover
The classic layout, characteristic of many models Pozis (for example, RK, RD series), involves placing a thermostat under the top metal refrigerator lid. In such units, the temperature control knob is placed outside, but the mechanism itself is hidden inside the housing. To get to it, you will have to remove the top panel, which is usually attached to self-tapping screws hidden under decorative plugs or plastic covers.
The search process in this case requires accuracy. First you need to dismantle the top cover by unscrewing the fixing screws around the perimeter. After removing the metal, you will see a layer of polyurethane foam insulation and a plastic casing, inside which the thermostatis hidden. Often it is mounted on a special bracket or bracket pressed against the wall of the chamber.
A feature of this design is that the capillary tube can be inserted into a technological channel inside the wall of the refrigerator. When dismantling, it is important not to damage the insulation and not to cut the tube with sharp metal edges. Contact such models are often protected by an additional plastic cap, which must be removed to check the voltage or replace the part.
☑️ Removing the top cover
If you see that the thermostat is heavily covered with frost or condensate, this may indicate a violation of the chamber’s seal or a malfunction of the system No Frost (if it is provided for by the design). In normal condition, the regulator body should be dry, although in freezers the presence of an ice crust on the tube is allowed.
Location in refrigerators with an internal lamp system
In a number of models Pozis, especially those that have a more modern internal chamber design, the thermostat can be integrated into the lighting control unit or located directly behind the lampshade. This solution allows you to make the interior space more aesthetically pleasing by removing protruding controls on the side wall. In this case, the adjustment knob may be located outside on the front panel, and the mechanism itself may be located deep inside.
To access the unit in this configuration, it is often necessary to remove the plastic shade of the lighting lamp. It is attached with latches or one screw. Under the lampshade you will find not only the lamp socket, but also the unit to which it fits capillary tube. This is the desired thermostat. This arrangement is convenient for replacement, since it does not require disassembling the entire refrigerator body.
However, you should be prepared for the fact that the space for maneuver will be limited. The plastic walls of the chamber are fragile, especially if the refrigerator has stood for several years without defrosting. When trying to remove thermostat from the seat, you need to act slowly, releasing the fixing clips. Damage to the plastic of the chamber can lead to moisture getting into the insulation, which can lead to corrosion and loss of cooling capacity.
⚠️ Attention: The plastic of the inner walls of the refrigerator becomes very fragile in the cold. Do not use excessive force when removing lampshades and covers to avoid breaking them.
In some modifications, a defrost sensor may be located next to the thermostat. Don't confuse these elements: the control thermostat has an adjustment rod that goes out, and the defrost sensor is just a sealed capsule at the end of the wire. Correct identification components is critical for successful repair.
Search specifics in models with No Frost and electronics
Refrigerators Pozis with system No Frost (or “Full No Frost”) have a more complex internal architecture. In them, the thermostat as a mechanical regulator is often replaced by electronic sensors, the signal from which is sent to the control module. These sensors can be located in different areas: on the evaporator, in the cold air supply channel or in the ventilation zone.
If your refrigerator is equipped with an electronic control panel on the door, then there may not be a mechanical thermostat with a handle inside the chamber at all. In this case, the “search” is transformed into diagnostics of electronic sensors. They look like small plastic “bullets” or cylinders mounted in technical holes on the back wall of the chamber or behind the plastic evaporator panel.
To access sensors in the system No Frost It is often necessary to remove the back panel inside the freezer or refrigerator compartment. Behind it lies an evaporator and a fan. The temperature sensor is usually pressed against the evaporator or built into the duct. Its replacement requires accuracy, since incorrect positioning of the sensor will lead to incorrect operation of the compressor and possible failures in the defrost cycle defrost.
| System type | Regulator type | Typical location | Difficulty of access |
|---|---|---|---|
| Mechanical (Static) | Capillary thermostat | Under the top cover or in the shade | Low |
| No Frost (Partial) | Mechanical + Sensor | Inside the chamber and behind the evaporator panel | Medium |
| Electronic control | Thermistor (Sensor) | In the air duct or on the evaporator | High |
| Combined | Mechanical | Side on the inner wall | Low |
Simply installing a new part, you may not get the desired result if the system “remembers” the malfunction. In such cases, it may be necessary to diagnostics using special equipment or cyclically turning off the power.
Algorithm for safe removal of the thermostat
Once you have accurately determined where is the thermostat in your refrigerator Pozis, you can begin to remove it. This process requires a sequence of actions to avoid damaging adjacent nodes. First, make sure the refrigerator is defrosted and dry, as water can get on the electrical contacts.
The first step is always to disconnect the wires. Before doing this, it is strongly recommended to take a photo of the connection diagram or mark the wires with a marker so as not to confuse them during assembly. contactsTypically the thermostat has 2 or 3 wires (phase, neutral, ground or lamp circuit). Carefully remove the terminals, being careful not to pull on the wires themselves, so as not to break them at the base.
Next is the removal of the regulator body itself. If it's a mechanical model, you'll need to remove the adjustment knob (it may be tight, but sometimes requires a gentle wiggle). Then the fastening nut is unscrewed or the latches are released. The most delicate part is removing the capillary tube. It must be pulled out smoothly, without jerking, making sure that it does not catch on sharp edges of metal or plastic.
⚠️ Attention: The capillary tube of the thermostat is filled with refrigerant under pressure. Puncture of the tube will lead to leakage of the substance and failure of the thermostat. Protect it from sharp objects!
If the tube is laid inside the wall channel, pull it out, holding the refrigerator wall with your other hand so as not to deform the channel. In some cases, the tube may be glued to the evaporator; then careful separation is required, perhaps using a hairdryer (at a minimum temperature) to soften the glue or ice.
Diagnostics and signs of malfunction
Understanding where the thermostat is located is useless without the ability to determine its malfunction. The main sign of a breakdown is incorrect operation of the refrigerator: it either does not turn on at all, or works without interruptions, freezing food to the point of stone. In the first case, the circuit is broken, and compressor does not receive a signal to start, in the second, the contacts are “stuck” in the closed state.
You can check the mechanical thermostat with a multimeter in continuity mode. At room temperature, the contacts should close (make a sound). If you place the sensitive part (can) in the freezer for 10-15 minutes, the chain should break. Lack of response to temperature changes indicates a malfunction thermostat.
It is also worth paying attention to the appearance. Carbon deposits on the contacts, melted plastic or swelling of the housing are clear signs that the part was operating with an overload or a short circuit current passed through it. In such cases, replacement is mandatory, even if the continuity test shows formal operability, since the reliability of such a unit is in question.
For electronic sensors, diagnostics are more complicated and require measuring resistance, which should change smoothly with temperature changes. Sudden jumps or an open circuit indicate a sensor failure. Remember that a sensor malfunction can simulate a breakdown of the main control module.
Is it possible to replace the thermostat with an analogue from another manufacturer?
Yes, it is possible, but with important reservations. The main attention should be paid to the temperature response range and the length of the capillary tube. If the range is wider or narrower than the original, the refrigerator will not work correctly (freezing too much or too weak). The length of the tube must be equal to or greater than the original one (the excess can be carefully twisted), but not less, otherwise the sensor will not reach the desired zone.
Why does the refrigerator click but does not turn on after replacing the thermostat?
The click indicates that the thermostat is trying to start the compressor, but the start relay or the compressor itself does not work. Perhaps during the replacement you accidentally damaged the wiring, or the problem lies not in the thermostat, but in the start-up relay, which could also have failed. It is also worth checking the voltage in the network.
How long does the thermostat last in Pozis refrigerators?
The average service life of a mechanical thermostat is 5-7 years of active use. However, with frequent power surges or regular defrosting in violation of instructions, this period may be reduced. Electronic sensors, as a rule, last longer, but are more sensitive to humidity.
Do I need to wait after installing a new thermostat?
Yes, after replacing the thermostat and turning on the refrigerator, it is recommended not to load it with food for 2-4 hours. Allow the system to return to operating mode so that the new regulator is correctly calibrated and turns off the compressor when the set temperature is reached. This will extend the service life of the new component.