Failure of the thermostat is one of the most common causes of temperature violations in household refrigerators. When the compressor stops turning off or, on the contrary, does not start at all, most often this sensor becomes the culprit. Thermostat It is responsible for maintaining the set temperature, opening and closing the electrical circuit depending on the sensor readings.
Many equipment owners immediately call a technician, but replacing this yourself assembly is quite realistic if you have a minimum set of tools and follow safety precautions. In this article we will analyze in detail the diagnostic and replacement process, and also explain what to look for when choosing an analogue for your model.
It is important to understand that before starting any work you must completely de-energize the refrigeratorunplug the plug from the socket. Ignoring this rule may result in electric shock or a short circuit in the control board, if it is present in your model.
Principle of operation and signs of thermostat malfunction
The thermostat is an electromechanical or electronic device that reads the temperature inside the refrigerator or freezer. Classic models use a bellows tube filled with gas or liquid that responds to thermal expansion. When the temperature reaches the set value, the contacts open and the compressor stops.
You can understand that thermostat is faulty by a number of characteristic signs. If the refrigerator works without interruption, turning food into ice, or remains silent for days, allowing the contents to defrost, the problem lies in the control system. Also, a malfunction may be indicated by a sharp click, after which the unit does not start.
There are several main symptoms that require immediate intervention:
- ❄️ The compressor hums continuously, without going into rest mode, even with minimal settings.
- 🧊 A “fur coat” or ice crust has formed on the back wall of the refrigerator.
- 🔌 The unit does not respond at all to being plugged in, although the light inside is on.
- 🌡️ The temperature of the food does not correspond to the set mode (too warm or too cold).
It is worth noting that similar symptoms may appear if there is a freon leak or a faulty start relay. Therefore, before ordering a new part, it is recommended to carry out an initial diagnosis so as not to waste money on spare parts that will not solve the problem.
Diagnostics and preparation for repair
Before starting disassembly, you need to make sure the diagnosis is correct. The easiest way to check is to close the thermostat contacts directly. If after this procedure the compressor starts and starts to cool, then the problem is in the sensor. However, this method requires caution and an understanding of electrical circuits.
To work, you will need a standard DIY kit. There is no need to buy expensive professional equipment, just basic tools that many people have in their garage or toolbox.
List of necessary equipment:
- 🔧 A set of screwdrivers (phillips and flat) for dismantling panels.
- 🔌 Multimeter or tester for “testing” the circuit for contact.
- ✂️ Pliers or pliers for working with wires and clamps.
- 🔦 Flashlight for illuminating the interior of the chamber.
If you are planning to replace the thermostat in a refrigerator with a system No Frost, please note that access to the sensor may be limited by the evaporator or plastic panels. In such cases, partial defrosting of the unit is often required for 10-12 hours so that the ice does not interfere with dismantling.
⚠️ Attention: When working with a multimeter, make sure that the device is set to resistance measurement mode (Ohm). If, when the probes are closed, the arrow does not deviate or the digital value does not change, check the batteries in the tester.
Removing the old thermostat
The process of removing the old sensor depends on the design of the refrigerator. In models with an internal regulator (handle inside the chamber), it is necessary to remove the plastic cover, which is usually held on by latches or one screw. The mechanism itself is hidden under it.
If the thermostat is moved outside (located on the top panel or in the lampshade), the task is simplified. You will need to remove the lamp shade, unscrew the fixing screws and carefully remove the control unit. The main thing here is not to damage the fragile plastic fasteners, which can be dry on old refrigerators.
Sequence of steps for dismantling:
- Remove the temperature control knob, if it is removable (pull it towards you or pry it with a flat screwdriver).
- Remove the protective panel or casing hiding the case thermostat.
- Take a photo of the wire connection diagram so that when installing a new sensor you do not confuse the contacts.
- Disconnect the wires from the terminals, first remembering their color markings.
- Carefully pull the capillary tube out of the hole in the chamber, trying not to bend it under acute angle.
Pay special attention to the condition of the capillary tube. This is a thin copper or aluminum element containing a temperature-sensitive gas inside. Deformation of the tube can lead to gas leakage and incorrect operation of the new thermostat, even if it is working properly.
☑️ Preparation for dismantling
Installing a new one thermostat
Installation of the new part is carried out in the reverse order. It is critical to choose a thermostat with similar characteristics. They may differ in the length of the capillary tube, operating temperature range and type of contacts. The product body is usually marked with markings, for example TAM-133 or K-59, by which you can find an exact analogue.
When installing, make sure that the capillary tube is laid along the same path as the old one. It should fit snugly against the wall of the evaporator or be in a special channel. If the tube dangles in the air, the sensor will read the temperature incorrectly, which will lead to frequent starts of the compressor or its downtime.
Table of popular thermostat analogues:
| Original (Danfoss/Thermo) | Analog (Klixon/Other) | Tube length | Application |
|---|---|---|---|
| TAM-133 | K-59 | 0.75 m | Single chamber refrigerators |
| TAM-145 | K-57 | 0.75 m | Freezers cameras |
| TAM-132 | K-50 | 0.75 m | Refrigerators with a weeping wall |
| 25T65 | K-56 | 0.90 m | Chest freezers |
After physically installing the part, connect the wires according to the previous photographs. Make sure the terminals are tight and not loose. If the contacts are oxidized, they can be carefully cleaned with fine sandpaper, but it is better to use new terminals if they are included.
Replacement features in different models
The design of refrigerators from different brands may differ significantly. For example, in models Atlant and Indesit thermostats are often located in the lighting shade or under the top cover. Getting to them is relatively simple by removing a few screws.
In refrigerators Bosch and Siemens with electronic control, the thermostat can be integrated into a common control unit or located behind the rear panel of the chamber. Here, replacement requires greater care, since it is easy to damage the plastic panel fasteners.
Nuances for popular brands:
- 🇧🇾 Atlant: Thermostats of the TAM series are often used. When replacing, it is important to install the sealing rubber correctly so that moisture does not get on the contacts.
- 🇮🇹 Indesit/Ariston: The capillary tube can be secured with a special clip on the evaporator. Do not forget to fix it during assembly.
- 🇩🇪 Bosch/Liebherr: In some models, access to the thermostat is possible only after