A sudden failure of the refrigerator Posis to maintain the set temperature often becomes an unpleasant surprise for the owners. If you notice that food in the main chamber has begun to quickly deteriorate, and the ice is melting in the freezer, or, conversely, the equipment is working non-stop without turning off, the reason may lie in a malfunction of the thermostat. This small but critical element is responsible for the cyclic operation of the compressor, turning it on and off at the right moment.
Independent replacing the thermostat is a completely solvable task for a person who has basic skills in handling tools and understands the basics of electrical safety. Repairers often call this part by different names: thermostat, temperature sensor, or simply “thermostat.” In models Pozis, especially in series RD, Sviyaga or Atlant (assembled under the brand), the replacement procedure has its own nuances associated with the design of the capillary tube.
Before starting disassembly, you need to make sure that the problem is really in the sensor, and not in a freon leak or compressor failure. If the motor hums constantly, but there is no cold, or it is silent, although it is warm in the chamber, most likely the culprit has been found. Correct diagnosis will save you money on buying unnecessary spare parts and time on unnecessary manipulations with equipment.
Diagnostics of a thermostat malfunction
The first step should always be accurate identification of the problem. The thermostat in the refrigerator Posis is a mechanical or electronic device that responds to changes in temperature inside the chamber. When the temperature reaches the set threshold, the contacts open and the compressor stops. If this does not happen, the food freezes into a “stone” or, conversely, defrosts.
There are several obvious signs indicating failure thermostat. Often, users ignore the first symptoms, believing that the equipment is simply “tired” or there is a power surge in the network. However, ignoring these signals can lead to more serious consequences, including overheating and combustion of the motor windings.
- ❄️ The compressor works continuously without turning off for hours, even if you turn the regulator knob to minimum.
- 🔥 The refrigerator does not work at all turns on, although the indicators are on and there is voltage in the socket.
- 💧 A “snow coat” forms in the refrigerator compartment or, conversely, the food thaws at maximum settings.
- 🔌 The thermostat housing has visible traces of melting or oxidation of the contacts (visible during disassembly).
⚠️ Attention: If the compressor hums but does not start, and after a few seconds there is a click and silence, it could be not only the thermostat, but also the start relay or the motor itself. Do not rush to change the sensor without checking the circuit.
For an initial check, you can try to “knock” on the thermostat body or sharply change the position of the regulator. If after these steps the motor starts or stops, then the problem is in the stuck contacts inside the sensor. Another effective method is to exclude the thermostat from the circuit: if the compressor starts when the wires are shorted, it means that the sensor does not send a signal to turn on.
Necessary tools and preparation of the workplace
High-quality repairs are impossible without the right tool. To replace the thermostat in the refrigerator Position you do not need complex industrial equipment, but a basic DIY kit is required. It is important to prepare everything in advance so as not to look for a screwdriver in a disassembled state, when your hands are busy with fragile elements.
The main tool will be a set of screwdrivers. You will need Phillips screwdrivers of different sizes to remove the panels and a straight screwdriver to manipulate the terminals. A multimeter (tester) will also be an indispensable assistant for “diagnosis” of contacts and checking the integrity of the circuit. Without it, replacement is done “at random”, which does not guarantee the result.
- 🔧 Set of screwdrivers (phillips PH1, PH2 and flat).
- 🔋 Multimeter for checking resistance and integrity of contacts.
- ✂️ Side cutters or pliers for trimming excess insulation or clamps.
- 🧤 Gloves to protect hands from sharp metal edges and possible residual coolant.
Be sure to ensure good lighting of the work area. The insides of the refrigerator are often hidden in the shadows, and poor light can lead to wiring errors. Also prepare a container for storing small fasteners so that they do not get lost.
⚠️ Attention: Before starting any work, be sure to disconnect the refrigerator from the power supply! Working with live electrical appliances is deadly. Unplug the plug from the socket before touching the internal components.
Removing the old thermostat
The process of removing a faulty part in refrigerators Posis depends on the specific model, but the general algorithm of actions is similar for most modifications. The thermostat is usually located inside the refrigerator compartment, hidden by a plastic cover or directly mounted into the wall. Your task is to get to it without damaging the evaporator and capillary tube.
First you need to remove the decorative trim or temperature control knob. In some models Pozis the handle is simply removed by force, in others you need to unscrew the screw hidden under the plug. Be careful: the plastic on old refrigerators becomes brittle and can crack if handled carelessly.
Removing the handle will give you access to the thermostat housing. It can be secured with latches or screws. Carefully press the latches or unscrew the fasteners. Then you need to gain access to the electrical contacts. They are often closed with an additional plastic cover, which should also be removed.
☑️ Checklist before dismantling
The most crucial moment is removing the sensitive capillary tube. It passes through the wall of the evaporator deep into the housing. Capillary tube very thin and easily bends or bursts. If it is damaged, the refrigerant will escape and repair will become uneconomical. Gently pull the tube out, making sure it comes out evenly from the mounting hole.
When the tube is released, disconnect the electrical wires. Before doing this, it is strongly recommended to photograph the connection diagram or mark the wires with a marker, since the color marking may differ from the standards. Unscrew the terminal screws or carefully remove the blocks, being careful not to pull the wires.
Installation and connection of a new sensor
Installation of a new thermostat is carried out in the reverse order, however, there are some technical subtleties here. The main rule: the new sensor must be a complete copy of the old one in terms of dimensions, capillary tube length and electrical parameters. For refrigerators Pozis thermostats of the brand TAM, K-59, K-57 or T-110.
Start by installing the capillary tube. Insert it into the hole until it stops, but without excessive force. The length of the tube is critical: if it is too short, the sensor will not sense the actual temperature of the evaporator; if it is too long, it may bend or rest against the back wall, which will lead to incorrect operation.
Nuances of the length of the capillary tube
The length of the capillary tube is not just a formality. If the new thermostat tube is longer than the old one, it can be carefully twisted into a ring with a diameter of at least 5 cm and secured in the free space behind the panel. Do not cut the tube or bend it at an acute angle under any circumstances, as this will disrupt the circulation of freon inside the sensor.
Next follows the connection of the electrical part. Use the photo or markings you took earlier to correctly connect the wires. Typically, in mechanical thermostats, the contacts are numbered (3, 4, 6, etc.). Make sure connections are tight and secure. Poor contact will lead to sparking, heating and repeated failure.
Fix the thermostat housing in its original place. Make sure that it does not loosen and fits tightly to the chamber wall, as the accuracy of the temperature reading depends on this. Install the decorative trim and adjustment knob.
⚠️ Attention: When installing, make sure that the wires do not get under moving parts or are pressed by sharp metal edges. Vibration of a running compressor over time can grind the insulation, which will lead to a short circuit.
Comparison of popular models of thermostats for Pozis
On the market of spare parts for refrigerators Position there are several main types thermostats. Understanding their differences will help you choose the right replacement if the original part is discontinued or out of stock. The main differences lie in the temperature range and contact design.
Below is a table that will help you navigate the main characteristics of common analogues. Please note that the parameters may vary slightly depending on the manufacturer's batch.
| Thermostat model | Contact type | Capillary length | Application |
|---|---|---|---|
| TAM-133 | Closes when decrease | 0.6 - 2.5 m | Single-chamber refrigerators |
| K-59 L1138 | Opens when lowered | 0.75 m | Double-chamber Pozis (main camera) |
| T-110 | Universal | 0.6 m | Budget models of Sviyag |
| K-57 | Opens when lowered | 2.5 m | Freezers and two-compressor |
When choosing an analogue, pay attention not only to the markings, but also to the appearance of the rod and the method of fastening. Some models may have an additional contact for an indicator or lamp, which is not used in your model. In this case, this contact simply remains free.
Checking performance and setting
After assembling the refrigerator, do not rush to load food into it. First you need to do a test run. Plug in the equipment and set the temperature regulator to the middle position (usually number 3 or 4). The compressor should start in a few seconds or immediately, depending on the current temperature in the chamber.
Allow the refrigerator to idle for 2-3 hours. During this time, it should gain temperature and automatically turn off. If this does not happen and the engine hums continuously, the thermostat may not sense the cold or is not set correctly. Check whether the sensitive tube fits tightly to the evaporator.
Setting the thermostat is a delicate process. If the refrigerator turns off too early, before the food has frozen, turn the adjusting screw (usually accessible through a special hole or under the handle) clockwise. If it turns off too late and freezes - counterclockwise. Make turns literally a quarter or half a turn, waiting for the result for several hours.
During operation, pay attention to the nature of the click when turning on and off. It should be clear and loud. A dull click or its absence may indicate that the mechanism inside the new thermostat is also defective or incorrectly installed.
Frequently asked questions (FAQ)
Is it possible to temporarily close the thermostat so that the refrigerator works?
Yes, this is possible for diagnosis or as a temporary measure. To do this, you need to connect the wires that went to the thermostat contacts, eliminating it from the circuit. However, remember that in this case the refrigerator will work continuously until you break the chain manually. This can lead to freezing of the evaporator and spoilage of food, so the equipment cannot be operated for a long time in this mode.
Why does the new thermostat click, but the compressor does not start?
If you hear a click, then the thermostat is working and gives a signal. The problem most likely lies in the compressor start relay, in the motor itself, or in the wiring. It is necessary to “ring” the motor windings and check the relay for sticking or breakage.
Is the thermostat for the freezer and refrigerator compartment different?
Yes, they differ in the temperature range of operation. The thermostat for the freezer compartment (for example, K-57) operates at lower temperatures (about -20...-24°C), while for the refrigerator compartment (K-59, TAM-133) the range is higher (about +3...+5°C). Installing an unsuitable sensor will lead to incorrect operation.
How to understand that the capillary tube is damaged during installation?
If, when bending or installing the tube, you heard a characteristic hissing sound or smelled oil (oil comes out along with freon from the sensor system), then the tightness is broken. Such a thermostat will not work and must be replaced.