Sudden defrosting of food or, conversely, turning vegetables into ice blocks is a sure sign that your refrigerator Indesit has ceased to correctly maintain the temperature. In most cases, the culprit of such anomalies is the thermostat, which is the “brain center” of the cooling system. It is this small device that makes the decision to turn the compressor on and off, based on the readings of temperature sensors inside the chambers.
However, simply buying the first part you come across is a risk that can lead to further breakdowns of an expensive unit. Thermostats for refrigerators Indesit can vary significantly in the length of the capillary tube, type of contacts and response range. If you make the wrong choice, the compressor will either work continuously, overheating, or will not start at all, leaving the food cold.
In this article we will look in detail at how to identify a malfunction, what types of thermostats exist for different models, and what to look for when purchasing. We will not use complex technical terminology where simple words can be used, but we will pay special attention to the nuances that even experienced craftsmen often miss. The correct selection of spare parts is half of a successful repair.
Symptoms of a malfunctioning thermostat
Before you go to the store for spare parts, you need to make sure that the problem lies in the thermostat, and not in a freon leak or a compressor malfunction. There are a number of characteristic signs that are highly likely to indicate failure thermostat. Ignoring these signals can lead to food spoilage and increased energy bills.
The most obvious symptom is the lack of cyclical operation of the refrigerator. In normal mode Indesit it should periodically shut down, giving the compressor a rest. If the unit hums without interruption, even when ice has already formed inside, this indicates that the thermostat contacts are “stuck” in the closed state. The mechanism simply does not receive the command to turn off, since the sensor “thinks” that the temperature is still too high.
⚠️ Attention: Continuous operation of the compressor for wear and tear can lead to its complete combustion in a matter of days. If you notice that the refrigerator does not turn off for more than 12 hours in a row, immediately unplug it and carry out diagnostics.
The opposite situation is also possible and occurs no less often. The refrigerator is silent, it’s warm inside, the food is spoiling, but when you turn the control knob or tap on it, you may hear a click and the unit will start. This indicates that contacts the inside of the thermostat has oxidized or the spring has weakened, which is why the circuit does not close automatically when the temperature rises.
Another important sign is incorrect temperature when the compressor is working. For example, in the main chamber everything is frozen into ice, but in the freezer, on the contrary, it is warm. Or the refrigerator is operating normally, but the food in it dries out or becomes covered with frost where it should not be. This indicates that calibration the device is knocked down, and it is sending incorrect signals to the actuators.
Design and principle of operation of the Indesit thermostat
To understand what kind of thermostat your refrigerator needs, you need to understand how it works. Models Indesit most often use mechanical thermostats, although in modern series they are increasingly found electronic sensors. The mechanical version is a sealed system filled with a temperature-sensitive gas or liquid.
The key element here is a capillary tube, which is attached to the evaporator or placed in the air duct. When the temperature inside the chamber changes, the substance in the tube expands or contracts, changing the pressure on the membrane. This pressure, in turn, opens or closes electrical contacts, controlling operation compressor. The length of this tube is a critical parameter when replacing.
Electronic thermostats, often called thermistors, operate on a different principle. They change their electrical resistance depending on temperature. Such sensors do not have moving mechanical parts and capillary tubes, which makes them more reliable, but also more expensive. To diagnose them, it is required multimeter, since it is impossible to visually determine the malfunction.
Why is the length of the tube so important?
If you install a thermostat with a shorter capillary tube, it simply will not reach the temperature measurement zone, and the refrigerator will not work correctly. If the tube is too long, it will have to be rolled into a ring, which can disrupt the circulation of the refrigerant inside the tube itself and distort the readings.
It is important to note that in two-chamber refrigerators Indesit with the No Frost system, the thermostat often controls only the evaporator, and not the air in the chamber directly. Therefore, even a small error in installing the sensor can lead to the system “thinking” that there is enough cold and turning off the cooling until the food in the chamber is defrosted.
Selection criteria: mechanics or electronics
When deciding the question “which thermostat for an Indesit refrigerator,” the first step is to determine the type of control system you have installed. Older and budget models Indesit (series C, B, IB) are equipped with a classic mechanical regulator with a rotary knob inside the chamber. Modern models (EF, DS, BIA series) are often controlled via an electronic panel from the outside, where the temperature is set in degrees.
If you have a mechanic, you need to look specifically for thermostat (thermostat). If you have electronics, you need temperature sensor (thermistor). These are fundamentally different parts that are not interchangeable. An attempt to install mechanics instead of electronics will require a complete rework of the control system, which is not economically feasible.
For mechanical thermostats, three parameters are critical: the number of contacts (2 or 3), the presence of grounding and the length of the capillary tube. Three-contact models are used in refrigerators with No Frost or defrosting function, where the third contact is responsible for the warning light or defrost valve. Installing a two-pin thermostat instead of a three-pin thermostat will cause the emergency defrost lamp to stop lighting up, although the refrigerator will work.
In the case of electronic sensors, the most important thing is resistance at a certain temperature (usually 25°C). The most common sensors have a resistance of 2 kOhm, 5 kOhm or 10 kOhm. If you install a sensor with a different resistance, the electronic control unit will receive false data, which will lead to chaotic switching on and off of the compressor or an error on the display.
Compatibility table and marking
Thermostat manufacturers, such as Klixon, Tam, Ranco or Orbital, use a complex a labeling system that can confuse an untrained user. However, for owners Indesit there are the most common articles that fit most models. Below is a table to help you navigate the main types.
| Marking (Analog) | Refrigerator type | Tube length | Features |
|---|---|---|---|
| TAM-133 / K-59 | Single chamber / Freezer | 0.73 m | 2 contacts, standard for old Indesit |
| TAM-145 / K-57 | Two-chamber (main chamber) | 1.3 - 2.5 m | 3 contact, for defrost system |
| Orbital 177 | Universal | 0.73 m | Often comes as a replacement for K-59, 2 contacts |
| Sensor 2 kOhm | Electronic control | Without handset | For models with display and buttons |
Please note that the length of the capillary tube in the table is approximate. In reality, it can vary from 0.5 to 3 meters depending on the volume of the fridge compartment. If you buy a thermostat with a tube shorter than required, you will not be able to properly attach the sensor to the evaporator, and it will “feel” the temperature of the air, not the surface, which will lead to incorrect operation.
When searching for spare parts in catalogs, always use the complete serial number (S/N) of your refrigerator Indesit. It is located on a sticker inside the chamber or on the back wall of the unit. Using this number, you can accurately determine the factory equipment and find out the original code of the spare part, which will eliminate the mistake when choosing an analogue.
☑️ Check before purchase
Step-by-step instructions for replacing the thermostat
Replacing the thermostat in the refrigerator Indesit is a procedure that you can do yourself if you follow safety precautions and care. The first step should always be to completely disconnect the device from power supply. Do not ignore this rule, as working with live electrical components is deadly.
Next you need to gain access to the thermostat. In models Indesit it is usually located inside the refrigerator compartment, hidden by a plastic cover or located behind the control panel. Remove the regulator handle (sometimes it simply comes off upwards, sometimes it requires careful prying), unscrew the fastening screws and remove the protective cover. Be careful with the plastic latches; they can be fragile.
Remove the old thermostat by disconnecting the wires. Before doing this, be sure to take a photo a connection diagram or sketch it, since the color marking of the wires does not always correspond to the standards. Pull the capillary tube out of the channel, being careful not to damage or bend it. Install the new thermostat, carefully laying the tube along the same path as the old one, and secure it in its original place on the evaporator.
⚠️ Attention: The capillary tube of the thermostat is filled with gas under pressure. It is strictly forbidden to bite, bend at an acute angle or pierce the tube. Damage to the tube will make the thermostat unusable, as gas will escape.
After connecting the wires according to your diagram and fixing the case, reassemble everything in the reverse order. Turn on the refrigerator and let it run for 2-3 hours. Check if it goes into operation and if the compressor turns off after reaching temperature. If the refrigerator got cold and turned off, the replacement was successful.
Frequent errors during diagnostics and replacement
One of the most common mistakes is replacing a working thermostat. Often users use the temperature controller when the problem lies in freon leak. If there is no refrigerant in the system, the thermostat will “think” that there is not enough cold and will run the compressor without stopping. Replacing the thermostat in this case will not help - the cold will not appear, and the compressor will burn out.
The second mistake is incorrect installation of the capillary tube. Its sensitive end should fit tightly to the evaporator in a specially designated slot or be secured with a clamp. If the tube hangs in the air of the chamber, the thermostat will respond to the air temperature, which changes more slowly than the evaporator temperature. This will lead to rare switching on and defrosting of food.
The third mistake is ignoring the wiring condition. Often the contacts on the thermostat itself are intact, but the wires going to them are burnt out or oxidized due to poor contact. Before installing a new part, be sure to clean the contacts on the wires and check their integrity. It is also worth checking the feed-through contact, if there is one, since a light bulb or fan is often powered through it.
Finally, many people forget about calibration. After installing a new mechanical thermostat, it may be necessary to adjust the screws under the handle (if they are accessible and protected by a seal, it is better not to touch them without experience). In some cases, the new thermostat may have a slightly different temperature range, and you will have to get used to the new knob position to achieve the usual cold.
FAQ: Frequently Asked Questions
Can I use a universal thermostat for Indesit?
Yes, you can. There are universal thermostats (for example, TAM or K series) that are suitable for many models of refrigerators. The main thing is that the length of the capillary tube, the number of contacts and the type of fastening match. Universal analogues are often even better than original components.
Why does the new thermostat click, but the refrigerator does not turn on?
This may indicate a malfunction of the compressor start relay or the compressor motor itself. A click means that the circuit is closed, but the current is not reaching the motor. It is also worth checking the integrity of the wires going from the thermostat to the compressor.
How to check the thermostat with a multimeter?
You need to remove the thermostat, immerse its sensitive tube in cold water (or put it in the freezer) and ring the contacts. In warm weather they should ring (if it is a normally closed contact), and in cold weather they should open the circuit. For an accurate check, you need knowledge about a specific model.
Where is the thermostat located in a two-chamber Indesit?
In most two-chamber models Indesit the thermostat is located inside the refrigerator compartment, in the upper corner, often hidden by a plastic panel next to the light bulb or freezing power control.