Sudden defrosting of food or, conversely, turning fresh vegetables into ice blocks are sure signs that the temperature control system has failed. In most cases, the culprit of these troubles is thermostat, which ceases to correctly read the readings inside the camera. For equipment owners Indesit replacing this unit on their own is a real way to save on calling a technician and quickly bring the refrigerator back to life.
The process of restoring functionality requires not so much high qualifications as accuracy and understanding of the principles of operation of the electrical circuit of the unit. Thermostat (or thermostat) is an electromechanical device that opens and closes the compressor power circuit depending on the evaporator temperature. If this mechanism is “stuck” or its contacts are burnt, the compressor either works without interruption or does not turn on at all.
Before proceeding with disassembly, you need to make sure the diagnosis is accurate, since symptoms of a thermostat malfunction can easily be confused with a breakdown of the defrost sensor or a freon leak. In this article we will analyze in detail the algorithm of actions for models Indesit with mechanical control, which are the most common in operation.
⚠️ Attention: All work on replacing electrical components must be carried out exclusively with the power supply disconnected from the network. Failure to comply with safety precautions can lead to electric shock or damage to the electronics of the refrigerator.
Diagnosis of a thermostat malfunction
The first step should always be a thorough diagnosis. If the refrigerator hums continuously and does not turn off, creating excess cold, or is silent and the temperature inside rises, these are classic signs of failure. However, before replacing, it is worth excluding simpler causes, for example, a loose door fit or a clogged drain hole. Indesit buzzes continuously and does not turn off, creating excessive cold, or is silent and the temperature inside rises, these are classic signs of failure thermostat. However, before replacing, it is worth ruling out simpler causes, such as a loose door fit or a clogged drain hole.
For mechanical testing, the “short circuit” method is often used. If you remove the terminals from the thermostat and connect them directly (after unplugging the refrigerator from the outlet!), and then turn on the power, a working compressor should start. If the motor starts working with a direct connection, then the problem lies precisely in the control circuit, and replacement of the thermostat is inevitable.
- 🌡️ The compressor works non-stop, even when it is already very cold inside the chamber.
- 🧊 Products in the refrigerator compartment freezes or, on the contrary, deteriorates due to heat.
- 🔌 When you turn the control knob to minimum or maximum, the click of the contact is not heard.
It is worth noting that in modern models with electronic control the role of a mechanical thermostat is performed temperature sensor, and the diagnostic procedure there will be different, requiring multimeter to measure resistance. In this manual, we focus on classic models Indesit with a rotary handle inside the chamber.
⚠️ Attention: If the compressor does not start when the contacts are directly closed, the problem may not be in the thermostat, but in the starting relay or the engine itself. Do not rush to buy a new part until you are sure that the compressor is working properly.
Preparation of tools and selection of a new part
The success of the repair half depends on the correctness of the selected spare part. Thermoregulators for Indesit may differ in the length of the capillary tube, the type of fastening and the location of the contacts. The most common models of manufacturers are Klixon, Tam or Orion. It is critically important to find the markings on the body of the old part in order to select an analogue with identical characteristics.
To carry out the work, you will need a standard DIY kit. The main tool will be a flat-head and Phillips screwdriver, as well as pliers for carefully removing the terminals. It would be a good idea to prepare a container to collect melt water if time is required during the defrosting process.
| Marking (example) | Type of contacts | Capillary length | Application |
|---|---|---|---|
| TAM-133 | 3 contact | 0.73 m | Refrigerator compartment |
| K59-L1950 | 3 contacts | 0.73 m | Universal (Indesit) |
| TAM-145 | 2 contact | 0.85 m | Freezer compartment |
| Orion K-59 | 3 contacts | 0.73 m | Klixon analogue |
When purchasing, pay attention to the length capillary tube. If the new tube is significantly longer than the old one, it can be carefully twisted into a ring, but under no circumstances should it be bent or broken, since there is a sensitive filler gas inside. Tightness systems are the key to correct operation.
Access to the thermostat: disassembling the refrigerator
In refrigerators Indesit access to the thermostat is most often provided from inside the refrigerator compartment. To do this, it is necessary to dismantle the plastic cover that hides the control mechanism. In some models, the regulator handle is simply removed by hand, in others you need to pry it off with a thin screwdriver.
After removing the handle and decorative trim, access to the thermostat housing mounting screws will open. Usually there are two or three. By unscrewing them, you can remove the control unit. Be careful: the capillary tube can be fixed in a special channel or pressed against the evaporator with a bar.
If the thermostat is located outside the chamber (in the engine compartment or on the rear wall), the algorithm of actions changes. In such cases, it is necessary to remove the back cover of the refrigerator or dismantle the top panel, depending on the design of the specific model Indesit. Always evaluate the tension of the wires before pulling the assembly.
- 🔧 Remove the top cover of the refrigerator compartment if the thermostat is built into the ceiling light.
- ❄️ Carefully bend the evaporator petals if the tube passes through them (only when completely defrosted!).
- 📸 Remember or take a photo of the order of connecting the wires to the contact group.
☑️ Preparation for dismantling
Removing the old thermostat
The most crucial moment is disconnecting the capillary tube. It is inserted into a special slot on the evaporator and can be secured with a bracket. The main task is to pull it out without damaging the thin copper shell. Any microcrack will lead to leakage of the filler gas, and the new device will immediately fail.
Electrical wires are attached to the terminals using spring clips or screws. To remove male-female terminals, it is convenient to use pliers, swinging the connector from side to side. Never pull the wires themselves, hold only the plastic or metal tip of the terminal.
If the tube passes through the door seal or wall cameras, proceed extremely slowly. Sometimes it is necessary to remove the entire internal plastic panel in order to gain free access to the tube passage. In models Indesit No Frost access may be limited by the evaporator, which will have to be partially dismantled.
⚠️ Attention: The capillary tube of the thermostat is filled with freon R134a or a similar gas under pressure. Damage to the tube will not cause an explosion, but will render the part unusable. Treat it like a fragile glass product.
Installation and connection of a new unit
Installation of a new one thermostat is done in reverse order. First, carefully insert the capillary tube into the seat on the evaporator. It must fit tightly, all the way, to ensure perfect thermal contact. If the tube dangles, the temperature will be read incorrectly.
The next step is the electrical connection. It is critical here not to mix up the wires. In thermostats with three contacts, one of them (usually marked with the number 3 or color) goes to the refrigerator light bulb, and the other two (1 and 2 or 4 and 6) are responsible for the compressor. An error will lead to the fact that the light will light only when the motor is running, or the motor will not start at all.
Typical contact diagram (check the markings on the case!):Contact 3 - Phase (L) from the mains
Contact 4 - To the compressor
Contact 6 - On the lighting lamp
After connecting the wires, install the thermostat housing in place and secure it with screws. Make sure the wires are not pinched by sharp plastic edges or touching moving parts. Assemble the decorative trims and set the adjustment knob to the position corresponding to the average temperature (usually the number 2 or 3).
What to do if the new part does not fit in dimensions?
If the body of the new thermostat is different, you can try to secure it with double-sided heat-resistant tape or make a simple metal bracket. The main thing is to ensure a tight fit of the sensitive element to the evaporator and secure fixation so that the vibration of the compressor does not loosen the fastenings.
Checking functionality and setting
After assembly, turn on the refrigerator. In the first minutes you should hear a characteristic click of the compressor starting. If the motor starts running, let the refrigerator Indesit run idle for at least 2-3 hours. This time is necessary to enter the mode and check the cyclical operation.
Normally, the refrigerator should reach the temperature, turn off and stand for some time. If it turns off but won't turn on again, the thermostat may not be feeling the heat and the tube is not installed deep enough. If it works without stopping, perhaps the tube does not fit tightly to the evaporator or the analogue is too powerful.
- ⏱️ The compressor operating time should be 40-60% of the total cycle time.
- 🌡️ The temperature in the main chamber should stabilize within +2...+5°C.
- 🔊 The sound of operation should be smooth, without frequent clicks of the relay (clocking).
Carry out the final temperature adjustment using the built-in thermometer placed in a glass of water in the center of the chamber. Adjust the position of the knob until the optimal values are achieved. Remember that calibration mechanical devices can take up to 24 hours.
Is it possible to replace the thermostat with a universal analogue?
Yes, you can. Universal thermostats (for example, K-59 series) are suitable for most Indesit models. The main condition is that the length of the capillary tube and the type of contacts match. If the tube is longer, its excess is carefully rolled into a ring inside the housing, trying not to break the seal.
Why does the refrigerator not turn off after replacement?
Most likely, the capillary tube is not fully inserted into the evaporator socket and does not feel real cold. The reason may also be incorrect adjustment of the handle or a defective new part. Check the tight fit of the tube to the surface of the evaporator.
Is it necessary to recharge the freon after replacing the thermostat?
No, it is not necessary. The thermostat is an electrical part that does not come into contact with the refrigerant inside the cooling system. The freon is in a sealed circuit, and if you carefully replace the thermostat, a violation of its tightness is excluded.
How can you understand that the problem is in the thermostat, and not in the board?
In refrigerators with mechanical control (twist), there is no electronic board, there is only a start relay. If you have a model with a display and buttons, there is a temperature sensor there. Checking it requires a multimeter: as the temperature changes, its resistance should change. If the resistance is unchanged, the sensor is faulty.