Modern Indesit refrigerator is a complex system where each element plays a critical role in maintaining optimal conditions for storing products. The heart of this system, so to speak, is not the compressor, but rather the thermostat, which controls the cycles of turning the motor on and off. Understanding how this unit functions allows the owner to independently diagnose most cooling problems, without resorting to the expensive services of service centers at the first symptoms.
It is based on the simple physics of the expansion of gases and liquids, converted into mechanical movement. When the temperature inside the chambers rises, the sensing element reacts to this change and closes the electrical circuit, starting the compressor. Conversely, when the specified parameters are reached, the circuit opens, stopping the operation of the unit. It is this endless cycle that ensures the stable temperature regime necessary for the preservation of food. operation principle lies the simple physics of the expansion of gases and liquids, transformed into mechanical motion. When the temperature inside the chambers rises, the sensing element reacts to this change and closes the electrical circuit, starting the compressor. Conversely, when the specified parameters are reached, the circuit opens, stopping the operation of the unit. It is this endless cycle that ensures the stable temperature conditions necessary for food preservation.
In this article we will analyze in detail the internal structure of the thermostat, the characteristic signs of its failure and the nuances that are important to consider when operating the equipment. Indesit. You will find out why the refrigerator may stop turning off or, conversely, not respond at all when plugged in. Accurate calibration of the thermostat at the factory is a critical parameter that cannot be reproduced at home without special equipment.
The design and principle of operation of the thermostat
Thermoregulator, or thermostat, in refrigerators Indesit most often it is an electromechanical device, although in modern electronically controlled models its functions are performed by a digital sensor. A classic mechanical device consists of a sealed bellows tube filled with freon or inert gas and a contact group. The bellows is connected to a capillary tube, which is laid along the evaporator or inserted directly into the fridge compartment.
As the temperature in the chamber increases, the gas inside the bellows expands, creating pressure on the membrane. This pressure is transmitted to the lever mechanism, which physically closes the contacts, applying voltage to the winding of the compressor. As soon as the motor begins to cool the space, the gas is compressed, the membrane returns to its original position, and the contacts open. This process occurs thousands of times over the life of the device.
It is important to note that in models with a system No Frost the thermostat is often responsible only for controlling the air temperature, while a separate timer or electronic unit is responsible for defrosting the evaporator. However, in classic two-chamber refrigerators with a weeping evaporator, it is the mechanical thermostat that is the main control element of the entire climate system.
⚠️ Attention: It is strictly forbidden to open the sealed bellows housing or damage the capillary tube. There is gas under pressure inside, and a violation of the tightness will make the device absolutely unsuitable for further use without the possibility of restoration.
Dew point and condensate
Inside the bellows there is not just gas, but saturated refrigerant vapors, which at certain temperatures can condense. It is the change in phase state (liquid-gas) that ensures the high sensitivity of the system to the slightest temperature fluctuations.
Typical symptoms of a malfunctioning thermostat
It is possible to determine that Indesit refrigerator thermostat has failed by a number of indirect signs that manifest themselves in the behavior of the unit. The most obvious symptom is the situation when the compressor runs continuously, without turning off, even when the food in the chamber is clearly frozen. In this case, the contacts inside the device are “stuck” in a closed state, and the signal to stop the motor is not received.
The opposite situation, when the refrigerator does not turn on at all, also often indicates a breakdown of the thermostat. If, when you turn the temperature control knob, you do not hear a characteristic click, and the compressor is silent, it means that the circuit is not closing. This may be a consequence of oxidation of the contacts or loss of tightness of the bellows, due to which the gas has evaporated and pressure is not created.
Unstable operation, in which the refrigerator either freezes too much or completely stops cooling, may indicate a “floating” fault. Sometimes the cause is not the device itself, but a broken contact in the wiring or incorrect adjustment of the regulator knob. It is also worth checking whether ice has frozen at the end of the capillary tube, which can distort the readings.
- ❄️ The compressor works without interruption, the products in the main chamber freeze.
- 🔇 Complete lack of response to plugging in and turning the regulator knob.
- 🌡️ The temperature in the chambers does not correspond to the set values on the regulator.
- 💡 The light bulb is on, but the engine does not start (if the starting relay is working).
It is worth considering that similar symptoms may appear if there is a freon leak or a malfunction of the starting relay. Therefore, before sinning on the thermostat, it is necessary to carry out a comprehensive review of the entire system. Owners often make the mistake of replacing a working appliance, when the problem lies in another unit. diagnosis the entire system. Owners often make the mistake of replacing a working device, when the problem lies in another unit.
Thermostat location in different Indesit models
The search for a thermostat depends on the specific model and year of manufacture of your Indesit refrigerator. In classic two-chamber models, such as series DF or TL, the thermostat is usually located inside the refrigerator compartment. The regulator handle is located on the inner wall or ceiling of the chamber, and the device body itself is hidden behind a plastic panel or directly under the handle.
In more modern models with electronic control, a mechanical thermostat may be absent altogether. Its function is performed by an air sensor, which transmits data to the main electronic control module. In such cases, “repair” consists of replacing the sensor or reflashing the board, which requires a skilled technician. Mechanical devices are often hidden under the top cover of the housing or behind a decorative strip in the upper part of the refrigerator compartment.
To access the device, in most cases it is not necessary to completely disassemble the unit. It is enough to remove the plastic casing covering the handle or dismantle the top cover of the refrigerator. However, in some models Indesit, the capillary tube of the thermostat can be fixed to the evaporator, which requires partial defrosting and careful handling of fragile elements of the system.
| Model / Series | Handle location | Control type | Access to the body |
|---|---|---|---|
| Indesit DF 416 | Inside the camera (left) | Mechanical | Removing the plastic cover |
| Indesit C 138 | Inside the camera (right) | Mechanical | Behind the top cover inside |
| Indesit NBS 18 | On the body outside | Mechanical | Removing the top cover |
| Indesit EF 18 | Electronic panel | Electronic | Behind the control panel |
Always consult the technical documentation or diagrams specific to your serial number before beginning disassembly.
Step-by-step instructions for replacing the thermostat
Replacement thermostat is a procedure that can be done with your own hands if you have basic skills and tools. The first step should always be to completely disconnect the refrigerator from the electrical outlet. Safety when working with electrical appliances is priority number one, and ignoring this rule is unacceptable.
After disconnecting, it is necessary to dismantle the elements that hide access to the thermostat. Carefully remove the temperature control knob, unscrew the mounting screws and remove the device body. Pay special attention to the capillary tube: it is very thin and breaks easily. It must be carefully disconnected from the evaporator or pulled out of the seat, remembering the immersion depth.
The next step is to disconnect the wires. Before doing this, it is recommended to label them or take a photo, as mentioned earlier. The new thermostat must have similar characteristics (temperature range, capillary length, type of contacts). Installation is carried out in the reverse order: connect the wires, fix the body, carefully insert the capillary tube and attach its end to the evaporator or in a special channel.
☑️ Algorithm for replacing the thermostat
After assembly, you need to turn on the refrigerator and check its operation. During the first hours of operation, the unit can work in enhanced mode, gaining temperature. If after 2-3 hours the motor turns off and the cycle repeats correctly, then the replacement was successful.
⚠️ Attention: Do not use excessive force when installing the capillary tube. Bending the tube at an acute angle or pinching it will lead to rupture and leakage of the sensitive fluid, which will disable the new thermostat instantly.
Diagnostics and performance testing
Before buying a new part, it makes sense to check the old one to make sure it is faulty. The easiest way is a visual inspection and “testing” with a multimeter. To do this, you need to remove the thermostat, disconnect the wires and close them together directly (if the design allows) or use the tester in resistance measurement mode.
If, when turning the knob to the “maximum” position or when cooling the bellows (for example, putting it in the freezer for a couple of minutes), the contacts do not click and the multimeter shows infinite resistance, the device is faulty. It is also worth checking the condition of the contacts: if they are burnt or oxidized, this can cause sparking and unstable operation.
In some cases, the problem lies not in the mechanism itself, but in a broken capillary tube. If you notice traces of oil or gas near the place where the tube is attached to the evaporator, the seal is most likely broken. In such a situation, repair is impossible; only a complete replacement of the unit is required.
The check also includes an assessment of the length of the capillary. If you are installing a universal thermostat, you may have to trim the tube or, conversely, carefully twist the excess length into a ring to match the original. Incorrect length can lead to incorrect temperature readings.
The nuances of operation and temperature settings
Correct setting of the thermostat extends the service life compressor and ensures the safety of products. In refrigerators Indesit the regulator scale usually varies from 1 to 5 or from Min to Max. The optimal position for year-round operation is considered to be the average value or slightly above average (for example, 3 out of 5).
Setting the regulator to maximum in the summer forces the compressor to work at its limit, which can lead to overheating and failure. In winter, on the contrary, in unheated rooms the refrigerator may rarely turn on, which is dangerous for compressors running on oil, which thickens in the cold.
It is important to ensure that food does not block the flow of cold air to the thermostat. If the sensor is covered with pots or bags, it will “think” that the chamber is warm and will cause the motor to run continuously. This will lead to the formation of ice and excessive energy consumption.
Regular defrosting (for models with manual defrosting) also affects the operation of the thermostat. A thick layer of ice on the evaporator insulates the capillary tube, causing the device to no longer read the temperature correctly. Maintaining the cleanliness of the heat exchanger is the key to stable operation of the entire system.
Is it possible to use a thermostat from another manufacturer?
Technically, this is possible if the mounting dimensions, capillary tube length and temperature range match. However, different manufacturers (for example Tam, Danfoss, K59) may have differences in contact characteristics and rod stroke. It is better to look for original analogues or proven replacements recommended for specific models Indesit.
Why does the refrigerator click but does not turn on?
The click indicates that the thermostat is trying to start the compressor by closing the contacts. If the motor does not start, the problem is most likely in the start relay, the compressor itself (turn-to-turn short circuit), or in the wiring. The thermostat in this case is probably working.
How often should you change the thermostat?
The service life of a high-quality thermostat is 10-15 years or more. It does not require scheduled replacement. Replacement is made only when obvious signs of a malfunction appear: temperature incontinence, continuous operation or complete failure to switch on.
Does the ambient temperature affect the operation of the thermostat?
Yes, it does. Most refrigerators Indesit are designed to operate in climate class SN-T (from +10°C to +43°C). If the room is colder than +10°C, the thermostat may not turn on the compressor often enough, which will lead to defrosting of food in the refrigerator compartment.
What to do if after replacement the temperature does not stabilize?
Perhaps the new thermostat has a different temperature range or the capillary tube is not installed deep enough. The cause may also be a freon leak or a compressor malfunction that was not diagnosed at the initial stage. The system needs to be rechecked.