A violation of the temperature regime in the refrigerator compartment is a signal that cannot be ignored if you value food freshness. Often the cause is the failure of the temperature sensor, known as thermostat. In household appliances of the brand Posis this unit is responsible for turning the compressor on and off depending on the heating of the evaporator.
Independent replacement of the element allows you to save a significant amount on the services of service centers, but requires accuracy and understanding of the device unit. Incorrect actions can lead to damage to the capillary tube or refrigerant leakage, which will turn minor repairs into an expensive procedure for refilling with freon.
Before proceeding with disassembly, you need to make sure that the problem lies in the mechanical regulator, and not in the start relay or the motor-compressor itself. In this article we will analyze in detail the process of diagnostics, preparation of tools and the algorithm for replacing the thermostat in various models of refrigerators Pozis.
⚠️ Attention: Any work on repairing refrigeration equipment must be carried out with the device completely disconnected from the power supply. Failure to comply with safety precautions when working with electrical appliances is life-threatening.
Diagnostics of a thermostat malfunction
The first sign of a thermostat failure is either a complete absence of cold, or, conversely, excessive supercooling of food to the point of ice. If the compressor hums continuously without turning off, or, on the contrary, is silent for days, and it’s warm inside, these are direct symptoms of a failure in the control circuit.
For an accurate check, the “short circuit” method is often used. If, when connecting the thermostat contacts with wires (bypassing the sensor itself), the compressor starts, then the problem is precisely in thermostat. However, it is worth considering that in modern models with electronic control, mechanical replacement may not be required, since they use electronic resistance sensors.
It is also worth paying attention to the condition of the capillary tube that extends from the regulator body. If traces of oil or mechanical damage are visible on it, the tightness of the system is broken and the sensor will not be able to correctly read the evaporator temperature.
Necessary tools and preparation
To successfully carry out the work, you will need a standard DIY kit, supplemented by several specific tools. It is important to prepare a work area with good lighting, since the internal cavities of the refrigerator are often darkened.
You will need the following tools:
- 🔧 Screwdrivers: Phillips and flathead (of different sizes for housing screws and fasteners).
- 🔩 Pliers or pliers (for working with terminals and clamps).
- 🔦 Flashlight (for illuminating the internal space).
- 🧤 Gloves (to protect hands from sharp metal edges).
- 📸 Smartphone (for photographing the wiring diagram).
Special attention please take photo recordings before starting disassembly. The wiring diagram for different models Position may differ, and an error during assembly will lead to a short circuit. It would also be a good idea to prepare a container for small parts so as not to lose screws during work.
Access to the thermostat in different models
The design location of the thermostat in refrigerators Pozis depends on the series and year of manufacture of the model. In most classic two-chamber models, access is achieved by removing the lighting lamp or decorative trim inside the refrigerator compartment.
In some modifications, especially built-in ones or with a system No Frost (although there are often electronics), the regulator can be hidden behind the back wall or located in a niche above the door. To gain access, you may need to remove the top cover of the refrigerator from the outside, which requires caution when unscrewing the fastening bolts.
If you are the owner of a model with a remote adjustment knob on the body, dismantling begins with removing the plastic handle. It is usually simply removed by hand or is held on a hidden screw under a decorative plug.
Secrets of access in complex models
In some older Pozis models, the plastic lamp shade can be glued or held on by very tight latches. Use a flathead screwdriver wrapped in cloth to carefully pry the edges without breaking the plastic.
Step-by-step removal instructions
The process of removing the thermostat requires consistency. First you need to free access to the assembly by removing all interfering plastic interior elements. Proceed smoothly, as plastic becomes brittle in the cold and breaks easily.
After gaining access to the thermostat housing, disconnect the electrical terminals. Usually they need to be carefully removed from the contacts, slightly rocking them from side to side. Do not pull on the wires themselves, so as not to break them at the base.
Then you should remove the sensitive capillary tube from the hole in the chamber. It can be attached with a special clamp or simply fit into the groove. Pull it out carefully, without sharp jerks, so as not to damage the thin copper tube filled with freon gas.
☑️ Dismantling algorithm
⚠️ Attention: The capillary tube of the thermostat is very thin and easily pinched. Under no circumstances bend it at an acute angle or use rough tools to pull it out.
Installing a new thermostat
When installing a new element, it is important to ensure an exact match to the model. Thermostats are marked with codes (for example, TAM-133, K-59), and replacing them with an analogue with other temperature characteristics will lead to incorrect operation of the refrigerator.
Installation is carried out in the reverse order: first, carefully insert the capillary tube into the chamber hole, then fix the housing with screws. After this, connect the electrical wires strictly according to the photograph or diagram taken earlier.
Pay special attention to the length of the capillary tube. The excess is usually neatly rolled into a ring inside the case or behind the back wall, avoiding creases. If the tube is too tight, it may burst when the compressor vibrates.
| Parameter | Standard value | Tolerable deviation | Note |
|---|---|---|---|
| Switch-on temperature | -12°C ... -14°C | ±2°C | Depends on the model |
| Switch-off temperature | +3°C ... +5°C | ±1.5°C | Middle chamber |
| Capillary tube length | 0.75 m - 1.5 m | Can be shortened | Curled into a coil |
| Operating voltage | 220-240 V | 50 Hz | Network standard |
Checking functionality and setting
After assembling all the elements and connecting the refrigerator to the network, do not rush to download products. Let the unit run idle for 2-3 hours. This will allow the system to enter operating mode and stabilize the temperature.
Check the compressor operating cycle: it should turn on when the temperature rises and turn off when the set parameters are reached. If the refrigerator freezes too little, you can try adjusting the screw on the thermostat itself (if available), but this should only be done if you have experience.
If the compressor hums but does not start, or, conversely, works without interruption, creating an ice crust, it is necessary to re-check the correct connection of the contacts and the integrity of the capillary system.
Modern models Pozis may have complex protection systems. If after replacing the thermostat the error does not disappear, perhaps the problem lies in the start relay or freon leak, which requires professional diagnostics.
Is it possible to replace the thermostat with an analogue of another brand?
Yes, it is possible if the mounting dimensions, the length of the capillary tube and temperature range of operation. However, it is better to use original spare parts or proven analogues (for example, Danfoss, Ranco), since cheap Chinese copies can quickly fail.
Why does the refrigerator turn on immediately after being turned off?
This may indicate sticking contacts inside the new thermostat or incorrect setting of the temperature threshold. Also, the reason may be a malfunction of the compressor start relay, which requires replacement.
Is it necessary to defrost the refrigerator before replacing?
Full defrosting is not necessary if access to the thermostat is in the upper part of the chamber. However, if you need to remove the back panel or work deep inside, it is better to defrost the unit so that water does not get on the electrical contacts.