Refrigerators Indesit are deservedly popular due to their reliability, but even the highest quality equipment requires intervention over time. One of the most common causes of loss of cold or, conversely, deep freezing of food is the failure of the temperature sensor. Understanding how it works Indesit refrigerator thermostatwill allow you to independently carry out initial diagnostics and, perhaps, avoid an expensive call to a technician.
The main task of this unit is to maintain a given temperature regime inside the chambers, opening and closing the electrical circuit of the compressor. The design of the device seems simple, but this is where many nuances lie that affect the operation of the entire cooling system. In this article, we will look at the internal structure, types of contacts and methods for checking the serviceability of the device.
Before disassembling, it is important to understand the basic principle: a thermostat is a mechanical switch controlled by the expansion and contraction of a gas or liquid in a sensing tube. Errors in diagnostics often arise due to a lack of understanding of the physics of the process, so we will pay special attention to the mechanical part of the device.
Operating principle and internal design
The basis of any thermostat installed in household refrigerators Indesitis a sealed system filled with refrigerant. This system consists of the bellows tube itself (capillary) and a corrugated balloon (bellows), which responds to changes in pressure inside the tube. When the temperature in the chamber rises, the gas in the tube expands, the pressure in the bellows increases, and it mechanically opens the contacts, starting the compressor.
The reverse process occurs during cooling: the pressure drops, the bellows compresses, and the circuit opens. Key element here is precisely the tightness of this system. If a microcrack has formed in the tube and the gas has evaporated, the device stops responding to temperature changes, and the compressor either does not turn on at all or works continuously.
⚠️ Attention: The sensitive thermostat tube is extremely thin and fragile. If carelessly removed from the mounting hole in the evaporator, it can easily be damaged, which will make the new device unsuitable for installation.
In addition to the bellows, inside the housing there is a system of levers and springs, as well as a group of electrical contacts. The linkage mechanism allows the user to adjust the spring compression force using a rotary knob or screw, thereby changing the temperature range at which switching occurs. It is this mechanism that is responsible for that very “click” that we hear when the refrigerator is operating.
Types of thermostats and contact markings
B refrigerators Indesit the most common thermostats are Italian-made brand Ranco or Thermo. They can be single-contact (they open only the compressor circuit) or two-contact (they open the compressor circuit and the circuit of the lighting lamp or fan). Understanding the markings on the case is critical for correct replacement.
The terminal designations are usually stamped on the device case. Standard markings for single-phase models include contacts “3”, “4” and “6”. Contact "3" is the phase input from the mains, "4" is the output to the compressor, and "6" is an auxiliary contact that can be used to turn on a lamp or overload indicator. In two-chamber models with the No Frost system, more complex circuits may be found with additional terminals for controlling the dampers.
- 🔹 Contact 3: Connecting the phase wire from the power cord or start relay.
- 🔹 Contact 4: Supply voltage directly to winding of the compressor motor.
- 🔹 Contact 6: Additional circuits (lamp, fan, indicator).
- 🔹 Grounding: Separate screw on the metal case for connecting the grounding conductor.
It is important to note that the location of the contacts may vary depending on the model year Indesit. Some modern thermostats have electronic filling, but mechanics still predominate in classic models. Always check the electrical diagram pasted inside the refrigerator compartment or in the technical documentation.
What do the numbers on the thermostat knob mean?
The numbers from 1 to 7 (or Min/Max) do not indicate degrees Celsius. They indicate the degree of compression of the control spring. Number 1 - minimum cooling (warmer), number 7 - maximum (colder).
Fault diagnosis: symptoms and testing
You can determine what is faulty by indirect signs. The most obvious symptom is that the compressor runs continuously without turning off, and the food in the refrigerator freezes. This indicates that the contacts are “stuck” in the closed state or the bellows has lost its seal and cannot open the lever. Indesit refrigerator thermostat faulty, it is possible by indirect signs. The most obvious symptom is that the compressor runs continuously without turning off, and the food in the refrigerator freezes. This indicates that the contacts are “stuck” in the closed state or the bellows has lost its tightness and cannot open the lever.
The opposite situation - the refrigerator is silent. The compressor does not make any sounds, the light in the chamber is on, but there is no cold. In this case, most likely, the contacts have oxidized and do not conduct current, or the sensitive tube has broken. For accurate diagnostics, you need to “ring” the device with a multimeter in resistance measurement mode.
To carry out the test, you need to remove the thermostat, disconnect the wires and close contacts “3” and “4” with a jumper. If after connecting to the network the compressor starts working, then the problem is in the sensor. If the engine is silent even with a jumper, you need to look for a fault in the start relay or the compressor itself.
⚠️ Attention: Before starting any diagnostic work, be sure to disconnect the refrigerator from the power supply. Working with live electrical circuits is life-threatening!
Table of temperature conditions and settings
To properly configure and understand the operation of the thermostat, it is important to know which temperature ranges are considered normal for different compartments. The thermostat in the refrigerator compartment Indesit is usually set to maintain the temperature in the range from +2 to +8 degrees Celsius.
Below is a reference table showing the dependence of the position of the regulator knob on the approximate temperature inside the chamber. Please note that these values may vary slightly depending on the load on the refrigerator and the ambient temperature.
| Handle position | Approximate temperature (°C) | Operating mode | Recommendation |
|---|---|---|---|
| 1 (Min) | +8...+9 | Minimum cooling | Summer or light load |
| 3 (Average) | +4...+5 | Normal mode | Daily use |
| 5 (Max) | +1...+2 | Intensive cooling | With a large load of products |
| 6-7 | 0...-1 | Freezing | Short-term, not recommended |
Setting the handle to the “Max” position or higher for a long time leads to increased load on the compressor and can cause freezing of the back wall of the chamber. Optimal mode for most models Indesit the handle position is considered between marks 2 and 3.
Step-by-step instructions for replacing the thermostat
If diagnostics confirm a malfunction, the thermostat must be replaced. The replacement process in refrigerators is Indesit generally standard, but requires care. First, remove the plastic cover from the regulator handle and unscrew the fastening screw, if any. Then carefully pull the thermostat housing out of its seat.
The next stage is working with the sensitive tube. It can be fixed in a special hole in the evaporator or pressed with a bar. It must be removed very carefully, being careful not to bend or damage it. The new device must have a tube of the same length and configuration as the old one, otherwise it may not be enough for proper installation.
Installing the new thermostat is done in the reverse order. Connect the wires according to the previously made diagram or color coding. After assembly, you need to check the tightness of the tube and only then turn on the refrigerator.
☑️ Checklist before turning on
Common mistakes during self-repair
Independent repair of refrigeration equipment is often accompanied by errors that can lead to more serious damage. One of the most common problems is using a thermostat with inappropriate temperature characteristics. Outwardly, they may be identical, but have different markings for on and off temperatures.
Another common mistake is incorrect placement of the sensitive tube. If it touches the walls of the chamber or other metal parts other than the evaporator, the temperature readings will be distorted. This will lead to incorrect operation of the compressor: it will turn on too often or, conversely, rarely.
Also, do not ignore the condition of the wire insulation. During operation, the insulation could dry out and crack. If you do not replace damaged wiring sections when installing a new thermostat, a short circuit may occur. Always use heat shrink or high-quality electrical tape to insulate connections.
⚠️ Attention: Technical specifications of refrigerators may vary depending on the specific series and year of manufacture. Always check the markings of the new thermostat with the data on the body of the old device before purchasing.
FAQ: Frequently asked questions
Is it possible to repair the old thermostat, or is it only necessary to replace it?
In 99% of cases, repairing the thermostat is impractical. Loss of bellows sealing or contact wear requires factory restoration. It is easier and more reliable to buy a new device with the same marking.
Why did the refrigerator start working longer after replacing the thermostat?
This may be due to the fact that the new thermostat has slightly different temperature thresholds. Also check whether the sensitive tube is installed correctly - it should be in tight contact with the evaporator.
How can you understand that the problem is in the thermostat and not in a freon leak?
If, when the thermostat contacts are closed with a jumper, the compressor turns on and starts to cool (cold appears on the shelves), then the system is sealed and freon is in place. The problem is in the control circuit.
Where is the thermostat located in a two-chamber Indesit?
In most models Indesit with two chambers, the thermostat is located in the refrigerator compartment. The adjustment knob is usually located on the inside wall or top of the chamber. In No Frost models, it can be hidden behind a decorative panel.