A sudden cessation of operation of the refrigerator or, conversely, its inability to turn off is always stressful for the owner, associated with the risk of food spoilage and the need for urgent repairs. In most cases, the culprit of such failures is thermostat, which ceases to correctly read the temperature inside the chambers. Understanding which control element is best suited for your model is the key to successfully restoring the unit's performance without extra costs.
Choosing the appropriate sensor is not just buying the first part you come across with a similar marking, but a technically sound decision that requires analysis of the characteristics.
Wrong selected thermostat can lead to the compressor working with overload or, on the contrary, the products will begin to defrost, so the selection issue must be approached with maximum care and knowledge of the markings.
Principle of operation and types of thermostats
Thermostat is an electromechanical device that opens or closes an electrical circuit depending on the temperature in the evaporator. Inside the capillary tube there is a sensitive element that responds to changes in the volume of gas or liquid during heating and cooling. It is this physical process that activates contact groupwhich controls the start of the motor.
There are two main types of devices: mechanical and electronic. Mechanical models, such as the TAM or K-59series, are still installed in most household refrigerators due to their reliability and low cost. Electronic analogues, often called thermistors, are found in modern models with a system No Frost and digital control, where they transmit data to the main controller.
Mechanical regulators are simple in design, but tend to wear out over time, losing the tightness of the capillary. Electronic sensors are more accurate, but are sensitive to power surges in the network. The choice of the “best” option depends on the design of your refrigerator: if it had mechanics, installing electronics without seriously altering the control circuit does not make sense.
⚠️ Attention: Trying to install a thermostat with different temperature response characteristics may lead to freezing of the evaporator or failure of the compressor due to frequent switching on.
Selection criteria: marking and compatibility
When searching for a replacement criterion, compatibility in size and length is required capillary tube. If the tube is too short, you will not be able to insert it into the evaporator to the desired depth, which will lead to incorrect temperature readings. A tube that is too long can be carefully rolled up, but this requires care not to damage the thin metal.
The second important parameter is the temperature range of operation. For single-chamber refrigerators, thermostats with markings TAM-133are usually used, which turn off the compressor when it reaches -12...-14°C. For two-chamber models with an upper freezer, TAM-112 or K-59are suitable, triggered at higher temperatures, about -20...-24°C on the evaporator.
It is also necessary to take into account the length of the rod and the type of fastening. The stem is a plastic or metal rod that fits into the regulator handle. If the rod is too long, the handle may rest against the body; if it is short, there will be play and poor transfer of force to membrane inside the device.
Comparison of popular thermostat models
The spare parts market is dominated by several manufacturers whose products have proven themselves to be the most reliable. The leaders are Italian brands Ranco i ITR, as well as Russian analogues, which are often licensed copies. Understanding the differences between them will help you choose the best option.
Thermostats of the TAM series (manufactured by ITR) are considered the “gold standard” for replacement in the post-Soviet space. They are distinguished by a durable housing, high-quality insulation and stable response characteristics. Their capillary tubes often have additional protection against corrosion.
Models of the K-59 (Ranco) series are also widespread, especially in Atlant, Indesit and Stinol refrigerators. They are more compact, but require more careful installation due to the lower mechanical strength of the capillary. The choice between them is often dictated by the availability of a specific model in stores, since they are comparable in reliability.
| Model | Refrigerator type | Shut-off temperature | Tube length (standard) |
|---|---|---|---|
| TAM-133 | Single-chamber | -12...-14°C | 0.75 m |
| TAM-112 | Double-chamber (top) | -20...-24°C | 0.75 m |
| K-59 L1102 | Double-chamber (top) | -20...-24°C | 0.75 m |
| TAM-125 | Freezer compartment | -24...-26°C | 0.75 m |
Symptoms thermostat malfunction
Diagnostics of the malfunction is the first step before purchasing a new part. The most obvious sign of failure thermostat is the situation when the compressor hums continuously, without turning off for hours. In this case, the contacts inside the sensor are simply “stuck” in a closed state, and the refrigerator does not receive a signal to stop.
The opposite situation, when the refrigerator does not turn on at all, may also indicate a problem. If, when you turn the regulator knob, you do not hear a characteristic click, and the light inside is on, it means that the circuit is broken and does not close even with forced cooling of the sensor. This indicates that contact group does not work or gas has evaporated from the capillary tube.
Sometimes a “floating” malfunction occurs when the refrigerator either works normally or stops cooling. This may be due to poor contact inside the thermostat itself or a leak in the system. In such cases, replacing a part is often the only way to guarantee stable operation of the unit.
⚠️ Attention: Before replacing the thermostat, make sure that the problem is not in the start relay or the compressor itself, as the symptoms may be similar.
How to check the thermostat with a multimeter?
To check Remove the thermostat, immerse its sensitive tube in cold water with ice for 2-3 minutes, then ring the contacts. If the device shows a break, the thermostat is faulty.
Instructions for self-replacement
Replacing the thermostat is a procedure accessible to a home handyman with basic skills, but requires compliance with safety precautions. The first step is to completely turn off the power to the refrigerator by removing the plug from the socket. Then you should dismantle the plastic cover that hides the thermostat and remove the control knob.
Next you need to carefully remove the old part, remembering or photographing the order in which the wires are connected. Often the wires are color coded, but it's best to double check the diagram. The new thermostat is installed in the reverse order, and the capillary tube must be inserted into the technological hole until it stops, being careful not to bend it.
After assembly, it is necessary to check the tightness and performance. Turn on the refrigerator and listen to the moment the compressor turns off. If the work and rest cycle corresponds to the norm (approximately 15-20 minutes of work and 30-40 minutes of inactivity), then adjustment it was successful.
☑️ Checklist for replacing the thermostat
Configuration and calibration after installation
After installing a new one thermostat it may take time to stabilize the temperature inside the cameras. Do not panic if during the first hours of operation the refrigerator does not behave quite as usual. The system must enter the operating cycle, which may take up to 24 hours.
If you notice that the food in the main chamber begins to freeze, and in the freezer, on the contrary, melts, you may need to adjust the position of the sensor tube. In some models, there is an adjustment screw under the sealing plate on the thermostat body, but it is not recommended to turn it without experience and gauge equipment, as it can reset the factory settings.
The best way to adjust it is to use the external knob on the front panel. Turn it smoothly, waiting for changes in the operation of the compressor. If the refrigerator stops turning off even at minimum values, the thermostat may be installed with an inappropriate temperature range.
Frequently asked questions and answers
You can Is it possible to use a thermostat from another manufacturer?
Yes, it is possible if the overall dimensions, capillary tube length and temperature response range are the same. The main thing is that the seat and rod fit your control knob.
Why does the new thermostat click, but the refrigerator does not turn on?
This may mean that the compressor itself, the start relay is faulty, or there is a break in the wiring. The thermostat closes the circuit properly, but the current does not reach the motor.
Do you need to defrost the refrigerator before replacing?
Complete defrosting is not necessary if you work quickly, but it is recommended to let the unit stand turned off for at least 30-40 minutes to equalize the pressure in the system and avoid condensation on the contacts.
How to determine that the capillary tube is too long?
If the tube protrudes significantly from the technological hole and it cannot be neatly laid inside the case without creating creases, then it is too long for your model.
Is it safe to shorten the capillary phone?
Absolutely not. The capillary tube is part of a closed system filled with gas. Shortening it will break the seal and render the thermostat unusable.