A sudden stop of the compressor or, conversely, its continuous operation are the first bells indicating a malfunction of the temperature control system. Thermal relay, or thermostat, acts as the main regulator, which supplies and turns off power to the engine depending on the readings of the sensor inside the chamber. If you notice that the food in the refrigerator Indesit began to deteriorate due to insufficient cold or, on the contrary, freeze, turning into ice, you cannot ignore these symptoms.
Diagnostics of this part does not always require calling a technician, since in many cases you can check the serviceability of the unit yourself using simple tools. A working thermal relay at room temperature should close contacts 3-4, and when the sensor is immersed in cold water, open the circuit. In this article we will analyze in detail how to identify a breakdown, what tools will be needed and what to pay attention to when replacing the control element.
Understanding the operating principle will help you not only fix the current problem, but also prevent more serious compressor breakdowns that may occur due to incorrect operation of the automation. You should not delay the check, since long-term operation of the engine without shutting down or its rare switching on leads to overheating and failure of expensive components.
Principle of operation and main symptoms of malfunction
Thermoregulator in refrigerators Indesit is an electromechanical device that responds to changes in temperature in the evaporator or inside the chamber. Inside the body there is a sealed flask with a gas-filled tube (bellows), which expands when heated and contracts when cooled. These physical movements are transmitted to the contact group, opening or closing the electrical power circuit of the compressor.
When a part fails, the refrigerator ceases to maintain the set temperature. Most often, users are faced with a situation where the motor-compressor either does not start at all or works non-stop, trying to cool the chamber to impossible values. In the first case, the food melts, in the second, the “fur coat” on the back wall freezes, and electricity consumption increases sharply.
The main signs of thermostat failure include:
- 🧊 The compressor does not turn on, although the light bulb is on and the network hum is heard.
- 🔥 The engine is running continuously, without turning off even after reaching a low temperature.
- ❄️ The refrigerator compartment is too warm, despite the maximum setting of the regulator.
- 💧 The appearance of frost or ice on the products and walls of the chamber.
It is important to understand that similar symptoms can be observed if the start relay is faulty or the compressor itself, therefore diagnosis must be comprehensive. However, it is the thermal relay that is one of the most common culprits of such problems in models Indesit of various years of manufacture.
Preparation for diagnostics: tools and safety
Before you begin disassembling and checking electrical circuits, you must completely protect yourself and the equipment. Any work inside an electrical appliance requires disconnecting it from the power supply. Unplug the cord from the outlet and provide access to the back wall of the refrigerator, where the compressor and attachments are usually located.
To carry out high-quality diagnostics, you will need a minimum set of tools that most home craftsmen can find. The key device here will be multimeter (tester), which allows you to measure resistance and check the integrity of the circuit. Without it, it is almost impossible to determine the internal state of the contacts.
☑️ Preparation for testing
You may also need:
- 🔧 A set of screwdrivers (phillips and flat) for removing casings.
- 🧤 Dielectric gloves for additional safety.
- 📸 Smartphone for photographing the wire connection diagram.
- 🧊 A container of cold water to check the sensor response.
Before removing the thermal relay, it is strongly recommended to photograph the location of the wires. The color marking may differ in different modifications Indesit, and an error during assembly will lead to a short circuit or incorrect operation of the system.
Removing the thermostat in Indesit refrigerators
The location of the thermostat depends on the model of your refrigerator. In most two-compartment models Indesit with a bottom freezer compartment, the thermostat is located inside the refrigerator compartment. It is hidden behind a plastic cover on the side wall or integrated into the temperature control unit.
To access the unit, you must carefully remove the plastic cover, which is usually held on by latches or one or two screws. Proceed with caution as the plastic in older models may be brittle. After removing the cover, you will see the thermostat itself with a capillary tube coming out of it, which goes into the evaporator wall.
The dismantling process includes the following steps:
- Remove temperature control knob by simply pulling it towards you.
- Unscrew the screws securing the thermostat housing to the inner wall.
- Carefully remove the housing, trying not to damage the capillary tube.
- Disconnect the wire terminals, first making sure there is no voltage.
In some models, especially the series Indesit C or ER, the thermostat can be located directly above the door or in the lampshade. In such cases, disassembly begins with removing the top decorative box. The capillary tube in such models is often secured with special clamps that need to be bent.
If your refrigerator is equipped with a system No Frost, the temperature sensor may be located in the air duct. In this case, access will require partial disassembly of the inner lining of the chamber, which requires greater caution.
Methods for checking a thermostat with a multimeter
The most reliable way to check thermal relay is to ring its contacts using a multimeter set to resistance measurement mode (Ohm). To begin, remove the relay from the refrigerator, but do not disconnect the wires yet if you are afraid of mixing them up, or carefully disconnect them, remembering the order.
At room temperature (about 20-25°C), the contacts of a working thermostat should be closed. Connect the multimeter probes to the appropriate terminals (usually these are the contacts going to the compressor). If the device shows one or infinity, the circuit is broken and the relay is faulty. If the value shows zero or close to zero, the circuit is intact.
For a more accurate check, it is necessary to cool the sensitive element. To do this, lower the capillary tube (about 5-10 cm) into a container of cold water (temperature about 3-5°C) or apply ice to it. After a few minutes, the contacts should blur, and the multimeter should show an open circuit.
| Relay status | Environment temperature | Multimeter readings | Output |
|---|---|---|---|
| Normal | Room (+20°C) | 0 Ohm (Sound) | Good |
| Normal | Cooling (+3°C) | ∞ (No sound) | Good |
| Faulty | Room (+20°C) | ∞ (No sound) | Breakage of contacts |
| Faulty | Cooling (+3°C) | 0 Ohm (Sound) | Stuck contacts |
Pay attention to the state of the contacts themselves. If they are blackened or oxidized, this can cause unstable operation even with formally correct dialing. In such cases, a complete assembly is recommended, since cleaning the contacts gives only a temporary effect. replacement node, since cleaning the contacts gives only a temporary effect.
What to do if you don’t have a multimeter at hand?
If there is no tester, you can assemble a simple “control” from a battery and a light bulb. However, this method is less accurate and requires caution when working with electricity.
Analysis of typical problems and visual inspection
Often, a breakdown can be determined before using measuring instruments, simply by carefully inspecting thermostat. Mechanical damage to the housing, traces of plastic melting or a characteristic burning smell indicate that a short circuit or overheating has occurred inside.
Pay special attention to the capillary tube. She is very thin and sensitive. If there are creases, cracks or traces of corrosion on it, the tightness of the bellows is broken. The gas from the tube may have evaporated, causing the relay to stop responding to temperature changes. It is impossible to restore the tightness at home.
⚠️ Attention! If you find traces of oil or liquid around the capillary tube fastening, this is a sure sign of depressurization. Such a relay can only be recycled and replaced with a new one.
Another common problem is the oxidation of the contact groups inside the housing. Over time, sparking when the circuit is opened leads to the formation of carbon deposits, which increases resistance and causes heating. Visually, this may manifest itself in darkening of the output terminals.
In models Indesit with electronic control, the fault may lie not in the mechanical sensor itself, but in the control board. However, mechanical thermostats are rarely found in such refrigerators. If you have an electronic module, diagnostics require checking the voltage at the output of the board.
Replacing the thermal relay: step-by-step instructions
If the diagnostics confirm malfunction, the only solution is to replace the unit. It is important to purchase a thermostat with similar parameters. There is always a marking on the body of the old relay (for example, K59, TAM 133), according to which you can select an exact analogue in specialized stores.
The process of installing a new element is carried out in the reverse order of dismantling. First, install the housing in place, secure it with screws, and only then connect the wires according to the photographs taken earlier. Make sure that the terminals fit tightly and do not loosen.
Installing the capillary tube is particularly difficult. It must be carefully inserted into the same hole from which the old one was removed and fixed in the evaporator channel to the same depth. Typically, the length of the working part of the tube is from 30 to 50 cm, twisted into a spiral inside the chamber.
⚠️ Attention! Never bend the capillary tube at an acute angle or stretch it. This can lead to instant failure of the new thermostat.
After assembling all the components and returning the decorative panels, you can turn on the refrigerator. For the first few hours, the device will operate in test mode, gaining temperature. At this time, do not open the doors frequently and monitor the cyclic operation of the compressor.
Frequently asked questions and answers (FAQ)
Is it possible to temporarily close the contacts of the thermal relay to make the refrigerator work?
Yes, this is possible for temporary diagnostics or emergency storage of products. Shorting the wires going to the compressor will cause it to run constantly. However, you cannot leave the refrigerator in this mode for a long time: the evaporator will become covered with ice, the food will freeze, and the compressor may burn out from overload.
Why does the refrigerator not turn off after replacing the thermostat?
Perhaps the capillary tube is not immersed deep enough in the evaporator or is in poor contact with it. Also, the reason may be incorrect adjustment of the screw on the thermal relay itself (if there is one) or installation of a relay with an inappropriate temperature range.
How to distinguish a breakdown of the thermal relay from a malfunction of the compressor?
If, when you turn on the network, you hear a quiet hum, but there is no start-up, and after a while the thermal protection (clicking) is triggered, most likely The problem is in the start relay or compressor. If the compressor is silent and does not hum, but voltage comes to it, the thermostat is to blame.
Where can I find the markings for selecting an analogue thermostat?
The markings are applied to the metal or plastic body of the thermostat itself. Look for designations like Ranco K59, Danfoss 077B or Tam 133. Also important is the parameter of the length of the capillary tube, which should be no less than that of the original.