A sudden breakdown of refrigeration equipment always takes you by surprise, especially when it comes to the loss of food. Often the cause of a violation of the temperature regime is the failure of the thermostat, which ceases to respond correctly to changes in the internal temperature of the chamber. Owners of household appliances Indesit may be faced with a situation where the compressor either does not turn on at all, or works continuously without turning off for rest.
Replacing this element requires care, but it is quite possible for a home craftsman who has basic skills in working with electrical circuits and tools. Thermostat is key a control system unit that opens and closes the electrical power supply circuit of the compressor. Incorrect installation or ignoring connection nuances can lead to repeated breakdown or even fire of the wiring.
In this article we will analyze in detail the process of diagnostics, dismantling the old regulator and connecting a new thermostat in Indesit refrigerators. We will look at the differences between mechanically controlled models, pay attention to contact markings and work safety. Understanding the principle of operation of this device will help you avoid common mistakes during repairs.
The principle of operation and diagnostics of a malfunction of the thermostat
Before you start disassembling the unit, you need to make sure that the problem lies precisely in the thermostat, and not in other components, such as the starting a relay or the compressor itself. Thermoregulator (or thermostat) is a sensitive element that responds to the temperature of the evaporator or air in the chamber. Inside the device there is a bellows tube filled with gas or liquid, which expands or contracts, mechanically opening the contacts.
The main symptoms of a malfunction of this unit in refrigerators Indesit are:
- 🔌 The compressor hums, but does not start, or does not make any sounds at all when plugged in.
- ❄️ A “fur coat” or ice forms in the refrigeration chamber, since the unit does not turn off and operates non-stop.
- 🌡️ The temperature in the chamber is higher than normal, food spoils, although the compressor works intermittently (periodically).
- ⚡ When checking with a multimeter, the contacts do not close even when the terminals are forcibly closed.
For accurate diagnosis, you need to get to the thermostat. In most models Indesit it is located inside the refrigerator compartment, under a plastic cover or directly on the temperature control knob. Remove the handle and protective casing to gain access to the body of the device.
⚠️ Attention: Before starting any work on diagnosing and replacing electrical components, be sure to disconnect the refrigerator from the electrical network! Working under voltage is dangerous to life and can lead to a short circuit.
Checking is carried out using a multimeter in continuity mode. Disconnect the wires from the thermostat contacts and connect the probes to the terminals. If when you turn the knob there is no click and the chain does not ring, the device is faulty. It is also worth inspecting the bellows tube for mechanical damage or leakage of freon filler.
Preparation for replacement and selection of a compatible analogue
The success of the repair directly depends on the correctness of the selected spare part. Thermostats for refrigerators Indesit may differ in the length of the capillary tube, operating temperature range, the presence of a third terminal for the indicator lamp and the type of fastening. Using an unsuitable part will lead to incorrect operation of the refrigeration circuit.
When choosing a new one thermostat pay attention to the following parameters:
- 📏 Length of the capillary tube: it should be equal to or greater than the length of the old one (the excess can be carefully laid in coils, but not bend!).
- 🔢 Marking: look for analogs with a similar alphanumeric code (for example, TAM, K, DANFOSS).
- 💡 Presence of a grounding terminal: the third terminal is usually used to connect an indicator light or grounding case.
- 🔧 Mounting type: Check whether the holes for screws or latches match with your old device.
The most common brand of thermostats found in Indesit equipment TAM or K-series. If you cannot find the exact original, installing a universal analogue with similar characteristics is acceptable. It is important that the temperature response range meets the requirements of your refrigerator model.
To carry out the work you will need the following set of tools:
- Phillips and flathead screwdrivers.
- Pliers or side cutters (for cutting the tube if it is too long).
- Multimeter.
- Insulating tape or heat-shrink tubing.
- Flashlight for illumination.
Removing the old thermostat in the Indesit refrigerator
The process of removing a faulty device requires care so as not to damage the plastic of the chamber and the insulation of the wires. In refrigerators Indesit the thermostat is usually hidden under a decorative panel or built into the temperature control unit. First, remove the regulator handle by pulling it towards you (sometimes you may need to pry it slightly with a flat-head screwdriver).
Next, you should unscrew the screws that secure the plastic trim. Be careful: the plastic on older refrigerators can be brittle. After removing the cover, you will see the thermostat itself, inserted into a metal or plastic case. Carefully remove it, being careful not to sharply pull the capillary tube, which may be attached to the evaporator.
The next step is to disconnect the wires. Before doing this, it is strongly recommended to photograph the connection diagram or sketch the location of the wires on the terminals. This is a critical point, since reversed contacts can cause a short circuit.
Remove the wires from the terminals. If they are oxidized or “sticky”, carefully clean them or use WD-40 to make removal easier. Then disconnect the bellows tube itself from the evaporator. In some models it is simply inserted into the hole, in others it is secured with a bracket or screw.
⚠️ Attention: The capillary tube of the thermostat is very thin and sensitive to creases. When removing the old device, do not use excessive force to avoid damaging the evaporator or other elements inside the chamber.
If the new thermostat has a longer tube, it can be carefully laid in rings in the free space behind the back wall of the chamber, maintaining a bend radius of at least 30 mm. A fracture of the tube will make the new device unusable.
Connection diagram and installation of a new thermostat
Installation of a new one thermostat is done in the reverse order of dismantling. The most critical stage is the correct connection of the wires to the terminals. There are usually markings on the body of the device, but these may be worn off or not obvious. The standard circuit for most single-chamber and double-chamber refrigerators Indesit looks like this.
Usually three terminals are used:
- 🔴 Terminal 3 (or L): the phase wire from the network is connected here (via the power cord).
- ⚫ Terminal 4 (or COM): common wire going to the compressor (via the start relay).
- 🟡 Terminal 6 (or ground): ground wire or indicator lamp.
The circuit may differ in some models. Below is a table of contact correspondence for common series of thermostats installed in Indesit:
| Thermostat type | Contact 1 (Input) | Contact 2 (Output to compressor) | Contact 3 (Additional) |
|---|---|---|---|
| TAM 133 | 3 (L) | 4 (COM) | Grounding |
| K-59 | L1 | L2 | Grounding |
| TAM 145 | 3 | 4 | Indicator |
| Universal | Network input | On relay | Ground/Lamp |
Connect the wires according to your diagram. Make sure the contacts are tight and not loose. If the terminals are oxidized, it is better to replace them or thoroughly clean them. After connecting the electrical part, install the thermostat housing in place and secure the capillary tube in the same position where the old one was.
☑️ Check before assembly
Assemble the plastic cover and install the adjustment knob. Do not over-tighten the screws to avoid cracking the plastic. Make sure that the handle rotates freely and has clear switching clicks.
Configuring and checking the system functionality
After assembling all the elements, you can begin testing. Plug in the refrigerator. In the first minutes you should hear a characteristic click of the compressor starting. If silence persists, it is possible that the thermostat contacts are not closing or the temperature range is incorrectly selected.
Turn the thermostat knob counterclockwise until it stops (to minimum cooling) and then slowly rotate it clockwise. At the moment when the compressor should turn on, you will hear a distinct click. If there is no click and the refrigerator does not start, try closing contacts 3 and 4 directly (for a short time!). If the compressor starts working, the problem is in the new thermostat (the range is faulty or the range is not suitable).
What to do if the compressor hums but does not start?
This may indicate a malfunction of the start relay or the compressor itself, even if the thermostat is working. Test the relay by replacing it with a known good one. Also, the cause may be low voltage in the network or a wedge of the motor.
It is important to set the temperature correctly. For normal operation of the refrigerator Indesit set the regulator knob to the middle position (usually this is number 3 or 4 out of 5-7 possible). After 30-40 minutes of operation, check the temperature inside the chamber. It should drop to +4...+6°C.
If the refrigerator “does not see” the temperature set and does not turn off, perhaps the capillary tube does not fit tightly enough to the evaporator. In this case, you will need to re-disassemble and fix the tube more tightly or use heat-conducting paste to improve contact.
⚠️ Attention: Technical characteristics and arrangement of elements may vary slightly depending on the specific modification and year of manufacture of the refrigerator. Always check the technical documentation of your model, if it is preserved.
Common mistakes during self-repair
Independent repair of refrigeration equipment is fraught with risks. Even experienced professionals sometimes make mistakes, not to mention beginners. One of the most common mistakes is ignoring the length of the capillary tube. If the tube of the new thermostat is too short, the sensitive element will not correctly read the temperature of the evaporator, which will lead to frequent switching on or, conversely, to defrosting of the products.
Another common mistake is incorrect connection of wires to the terminals. By mixing up the input and output, you can apply voltage directly to the chassis or create a short circuit in the control circuit. Always double-check the connection diagram before final assembly.
It is also worth mentioning the misdiagnosis. Problems with freon leakage are often mistaken for a thermostat malfunction. If there is no refrigerant in the system, the thermostat may be fine, but there is simply nowhere to get the cold. In this case, replacing the regulator will not work.
Do not forget about safety. The use of poor quality electrical tape or poor contact between the wires can lead to heating and melting of the insulation inside the chamber, which can lead to a fire. All connections must be reliable and insulated.
FAQ: Frequently asked questions
Is it possible to install a thermostat with a different marking if the original is not on sale?
Yes, it is possible if the main parameters match: the length of the capillary tube, the temperature range and the type of fastening. Universal thermostats are often suitable, but may require additional adjustment or adjustment of the tube.
Why does the new thermostat click, but the compressor does not turn on?
There may be several reasons: the starting relay is faulty, the compressor is burned out, there is an open circuit between the thermostat and the relay, or there is no voltage at the input to the thermostat. It is necessary to test the circuit with a multimeter.
How often do you need to change the thermostat in the Indesit refrigerator?
The service life of the thermostat is on average 5-7 years, but it can last longer if the mains voltage is stable. Replacement is required only when signs of malfunction appear.
Is it dangerous to change the thermostat yourself?
The replacement process is mechanically simple, but involves working with electricity. If you are not confident in your knowledge of electrical engineering, it is better to entrust the work to a professional to avoid electric shock or damage to equipment.
What to do if the capillary tube of the new thermostat is longer than the old one?
Excess tube can be carefully laid in rings behind the back wall of the refrigerator compartment. The main thing is not to bend the tube at an acute angle and not to damage its shell, since there is a sensitive medium inside.