Modern household appliances, such as refrigerators Aristonare complex systems where each element is responsible for maintaining an ideal microclimate. When the equipment stops freezing or, conversely, begins to freeze food to the point of ice, the first thing experts advise is to check the thermostat or temperature sensor. Understanding exactly where it is located is a key step for successfully diagnosing a malfunction without calling a specialist.
In most models, including the popular series Ariston MBA or Quartz, the sensors are hidden from the user's eyes to ensure an aesthetic appearance and protection from mechanical damage. Their location directly depends on the type of cooling system: drip or No Frost. In the first case, the sensor is often hidden in the lampshade or on the back wall; in the second, it is built into the evaporator defrost system, access to which requires partial disassembly.
Do not panic if you find that your refrigerator Ariston is not working correctly. Often the problem is solved by replacing an inexpensive element that has failed. It is important to know that in Ariston refrigerators, sensors with a resistance of 10 kOhm most often fail at room temperature, and it is these elements that you need to look for for replacement. Let's look in detail at how to find this component in different zones of the refrigerator compartment.
The principle of operation and types of temperature sensors in Ariston
Before you start searching, you need to understand what we are looking for. Refrigerators Ariston use thermistors (NTC), which change their electrical resistance depending on the ambient temperature. Electronic module reads these changes and makes a decision: turn on the compressor, start the fan or activate the defrost heating element. Without a working sensor, the “brain” of the refrigerator is blind and cannot control the temperature.
Depending on the design, sensors can be immersion, contact or air. Submersible ones are usually located inside the evaporator tubes, contact ones are attached to the surface of the metal wall, and air ones measure the temperature of the gas in the chamber. In refrigerators Ariston the most common are contact sensors mounted on the back panel or in special niches.
⚠️ Attention: Before starting any work to find the sensor, be sure to disconnect the refrigerator from the power supply. Working with live electrical wiring and internal components is deadly and can lead to failure of the electronic control module.
There is a misconception that the temperature sensor and thermostat are the same thing. Older mechanical models used a capillary tube thermostat that physically opened the contacts. In modern Ariston electronics reigns, and thermistor only transmits the signal, and the decision is made by the board. This makes the diagnosis more accurate, but requires an understanding of the electrical parameters.
Location of the sensor in the refrigerator compartment
If your refrigerator Ariston has stopped maintaining the set temperature in the upper compartment, you should look for the faulty element there. In models with a drip defrosting system, the sensor is often hidden behind a decorative trim on the back wall. To get to it, sometimes it is enough to remove the shelves and carefully move the plastic panel without removing it completely.
In some modifications, especially built-in series, manufacturers hide the sensor in the lampshade. This is logical, since there is always access to the internal volume, and the sensor quickly responds to the opening of the door. However, be careful: the plastic becomes brittle over time, and careless movement can lead to breakage of the mount canopy.
To access the sensor in the rear wall, you may need the following procedure:
- 🔌 Completely defrost the chamber within 12-24 hours.
- 🔩 Remove all shelves and drawers to gain access to the back wall.
- 🛠 Carefully unscrew the screws holding the back plastic panel (if visible).
- 👀 Inspect the space behind the panel: the sensor looks like a small cylinder with two wires.
Often the sensor is fixed in a special hole or pressed against the wall with a bracket. Its wires go in a common harness to the control unit. If you see oxidation on the contacts or melting of the insulation, this is a sure sign that thermistor or its wiring requires replacement. Visual inspection helps to weed out mechanical damage.
Searching for a sensor in the freezer compartment and the No Frost system
The situation with the freezer compartment in refrigerators Ariston with the system No Frost much more complicated. Here, temperature sensors are built directly into the air circulation and defrost system of the evaporator. They are located behind the back panel of the freezer, which is hidden by a layer of polyurethane foam or plastic. You won’t be able to get there “just like that.”
The main defrost sensor is attached to the evaporator fins. It is he who informs the module that the ice has melted and gives the command to turn off the heating element. If this element is faulty, the refrigerator may either not thaw at all (an ice coat forms), or it may constantly heat up, defrosting food. Access to it requires complete disassembly of the freezer compartment.
☑️ Checklist before disassembling the freezer
The process of finding the sensor in the freezer looks like this:
- Remove all drawers and the top cover of the freezer compartment.
- Remove the fan (if it interferes with access to the panel).
- Unscrew the screws around the perimeter of the rear wall.
- Carefully bend or remove the panel to see the evaporator (copper or aluminum radiator).
On the evaporator you will see one or two sensors secured with clips. One is responsible for the air temperature, the other for the defrost temperature. In models Ariston they often have color-coded wires, but you should not rely on color alone, since the color scheme may change in different batches of assembly. It is better to check the electrical diagram of a specific model.
Diagnostics and performance testing
Just finding the sensor is not enough, you need to make sure that it works. To do this, you will need a multimeter switched to resistance measurement mode (Ohm). Working sensor at room temperature (about 20-25°C) it should show a resistance of around 4.6–5.2 kOhm (for some models 10 kOhm). The exact values depend on the specific modification of the refrigerator Ariston.
It is better to check in dynamics. Measure the resistance of the sensor at room temperature, then put it in a glass of warm water (not boiling water!) and monitor the readings. The resistance should gradually decrease as it heats up. If the device shows a “break” (infinity) or “short circuit” (zero), or the readings do not change when heated, the element is faulty.
| Ambient temperature | Expected resistance (type 5 kOhm) | Expected resistance (type 10 kOhm) | Status |
|---|---|---|---|
| +25°C (room) | ~5.0 kOhm | ~10.0 kOhm | Normal |
| 0°C (melting ice) | ~15.0 kOhm | ~30.0 kOhm | Normal |
| -18°C (freezer) | ~40-50 kOhm | ~80-100 kOhm | Normal |
| Any temperature | 0 kOhm or ∞ | 0 kOhm or ∞ | Faulty |
If you find that the sensor is “lying” (readings differ from the table ones by more than 20%), it must be replaced. Even a slight deviation can cause the refrigerator Ariston to work intermittently, turning on too often or too rarely. This directly affects the service life of the compressor.
The process of replacing the thermistor
Replacing the temperature sensor in the refrigerator Ariston is a procedure that requires care. After you have purchased an original spare part or a high-quality analogue with identical characteristics, you can begin installation. The main rule: never leave wires simply twisted. In conditions of high humidity and vibration, such twisting will quickly oxidize and burn.
Use soldering to connect the wires of the new sensor to the refrigerator wiring. Be sure to insulate the soldering area with heat shrink tubing or high-quality electrical tape that is resistant to low temperatures. Ordinary adhesive tape or cheap electrical tape will dry out in the cold and fall off, which will lead to a short circuit.
What will happen if you install a sensor with a different resistance?
If you install a sensor with an inappropriate resistance value, the operation algorithm of the refrigerator will be disrupted. The compressor may work without stopping, trying to reach an unattainable temperature, or not turn on at all, believing that the chamber is already cold. This will lead to food spoilage and compressor failure.
After installing the new element, reassemble the refrigerator in the reverse order. Make sure that all panels are in place and that the wires are not pinched anywhere. Turn on the equipment and let it run for several hours, monitoring the temperature in the chambers using an external thermometer. Stabilization of the mode may take up to 24 hours.
Typical mistakes during self-repair
Independent repair of refrigerators Ariston is fraught with a number of errors that can turn a minor breakdown into a major problem. One of the most common mistakes is trying to replace the sensor without defrosting. Ice accumulated on the evaporator can hide the fasteners, and using force to chip the ice often leads to breakdown of the evaporator tubes with freon.
Another common mistake is ignoring the tightness of the connections. Moisture in the refrigerator compartment is a constant companion. If you have poorly insulated the contacts of the new sensor, after a week or two corrosion (oxidation) will destroy the connection, and the repair will have to be repeated. Always use materials designed to withstand aggressive, damp environments.
⚠️ Attention: Do not use regular office tape or fabric-based tape to insulate wires. At low temperatures, the glue stops holding and the material becomes tanned. Use only specialized electrical insulating tape or heat shrink.
Also, users often confuse the temperature sensor with the defrost sensor. Although they may be structurally similar, their parameters (temperature coefficient of resistance) may differ. Installing a defrost sensor instead of a temperature sensor (or vice versa) will lead to incorrect operation of the electronics Ariston. Always check the markings on the body of the part.
Frequently asked questions (FAQ)
Is it possible to operate an Ariston refrigerator without a temperature sensor?
Theoretically, some models can start if the sensor circuit is shorted, but this is extremely dangerous. The refrigerator will operate in emergency mode, either freezing continuously or not turning on at all. This is guaranteed to lead to spoilage of food and possible failure of the compressor due to overload.
Where to buy an original sensor for an Ariston refrigerator?
It is best to look for original spare parts in authorized service centers or specialized stores of spare parts for household appliances. When ordering, be sure to indicate the full model number (PNC) of your refrigerator, which is located on a sticker inside the chamber. Analogs can be found in radio parts stores, knowing the resistance.
Why did the refrigerator not work after replacing the sensor?
There may be several reasons: the new sensor itself is faulty (defective), poor contact at the soldering point, a diagnostic error (the problem was not in the sensor, but in the control module or compressor), or the refrigerator did not pass the self-diagnosis cycle. Try disconnecting the device from the network for 15-20 minutes to reset the errors.
How to understand that the temperature sensor is lying?
If the refrigerator turns off when it is still warm in the chamber, or works without interruption, creating excess cold, and the compressor is working, most likely the sensor is transmitting incorrect data. Accurate diagnostics can only be carried out using a multimeter and thermometer, comparing the actual temperature with the resistance of the sensor.