A sudden cessation of cooling or, conversely, excessive freezing of food in the refrigerator Ariston often indicates a failure in the thermoregulation system. The electronic control module stops receiving correct data about the microclimate inside the chambers, which is why the compressor operates chaotically or does not start at all. In most cases, the culprit is a failed temperature sensor, which requires immediate checking and possibly replacement.
Diagnostics of this unit does not always require calling a technician if you have basic skills in working with electrical appliances and a multimeter. Thermal sensor is a thermistor, the resistance of which varies depending on the ambient temperature. Understanding the principle of its operation will allow you to independently determine whether the problem lies in the electronics or in the mechanical part of the refrigeration unit.
In this article we will analyze in detail the algorithm for identifying a malfunction, consider the characteristic symptoms of a breakdown and provide reference data for verification. Ariston refrigerators equipped with a reliable system self-diagnosis, but visual inspection and measurements with the device give a more accurate result than just trusting the indication on the panel.
Main signs of a thermal sensor malfunction
Before you start disassembling the equipment, you need to make sure that the symptoms point specifically to the sensor and not to a freon leak or compressor failure. The first and most obvious sign is a violation of the temperature regime when the engine appears to be working properly. If you notice that the food in the main chamber begins to deteriorate, and there is no frost on the walls of the freezer, although the compressor is humming, this is a reason to be wary.
Often the refrigerator Ariston gives signals about the problem through the display system. Alarm lights or temperature indicators may flash on the display. In models without a screen, the device may emit periodic sound signals, warning the owner of a critical increase in temperature inside the chambers. Error codes, such as F01, F04 or F06, often indicate an open circuit or short circuit in the sensors of different zones.
⚠️ Attention: If the refrigerator makes strange sounds (gurgling, whistling) and does not cool, but the sensor shows normal resistance, the problem may be a refrigerant leak, and not in the electronics.
Another symptom is the continuous operation of the compressor without shutdowns. If thermistor"stuck" in the low temperature position, the control module will assume that it is warm in the chamber and cause the motor to wear out. This leads to the formation of an ice coat in the refrigerator compartment and a significant increase in energy consumption.
The location of the sensors in different Ariston models
The design of refrigerators Ariston can vary significantly depending on the series and year of manufacture. In classic two-chamber models with a No Frost defrosting system, the sensors are usually hidden behind plastic panels inside the chambers. The main sensor that controls air temperature is often located at the top of the refrigerator compartment or built into the evaporator housing.
In systems No Frost critical is the defrost sensor, which is located directly on the evaporator, often built into an aluminum profile or mounted on tubes. Getting to it is more difficult, since it requires complete dismantling of the back wall of the freezer. An error in determining its location can lead to damage to fragile plastic fasteners.
- 📍 Refrigerator compartment: Often located in the ceiling part or built into the lampshade.
- ❄️ Freezer compartment: Hidden behind the back panel, next to the evaporator and fan.
- 🔌 Defrost zone: Fixed on the evaporator tubes, often in a special sleeve for better contact.
To accurately determine the installation location in your model Ariston it is recommended to study the technical diagram, which may be located under the plastic cover of the thermostat or in the user manual. If the diagram is lost, a visual search begins with inspecting all plastic elements that have wires going deep into the body.
Hidden sensors in advanced models
Some modern Ariston models with the Multi-Air Flow function may use additional sensors in the air ducts, which are almost impossible to replace without completely disassembling the air ducts.
Preparation for diagnostics: tools and safety
A high-quality check is impossible without the proper tools. The main diagnostic device will be multimeter (tester), capable of measuring resistance in Ohms. Without this device, the check will be only indirect and will not guarantee the serviceability of the part. You will also need a set of screwdrivers (Phillips and flathead) to remove the panels.
Before starting any work, you must completely turn off the power to the refrigerator. Unplug the power cord and wait 10-15 minutes for the capacitors on the control board to discharge. This safety rule cannot be ignored, since even when turned off, residual voltage may remain in the circuit.
☑️ Preparation for diagnostics
For ease of work, prepare a container for defrosting ice if you plan to get to the sensor in the freezer of the No Frost system. It would also be a good idea to have electrical tape or heat shrink on hand, since after checking the wires may have to be re-insulated. Contact connections must be perfectly clean and dry.
Step-by-step instructions for dismantling and testing
The verification process begins with access to the sensor itself. In the refrigerator compartment, it is usually enough to remove the plastic cover at the top or dismantle the lamp shade. In the freezer, you will have to remove all the shelves and drawers and carefully unscrew the screws securing the back wall. Be careful not to break the plastic latches.
After removing the sensor, visually inspect its body and wires. There should be no traces of melting, cracks or oxidation of the contacts. If there are no visual defects, we proceed to instrumental inspection. Switch the multimeter to resistance measurement mode (20 kOhm or 200 kOhm range, depending on the model).
⚠️ Attention: Do not try to measure the resistance of a sensor connected to the control board! You could burn out your refrigerator's processor. The sensor must be completely disconnected from the electrical circuit.
Connect the multimeter probes to the sensor contacts. At room temperature (about +20...+25°C), a working thermistor should show resistance in a certain range. For most models Ariston this value ranges from 4.5 to 6.5 kOhm. If the device shows "1" (infinity) or "0" (short circuit), the sensor is faulty.
Table of correspondence between temperature and resistance
Understanding How resistance changes with degrees is key to accurate diagnosis. Thermistors have a negative temperature coefficient (NTC), which means the lower the temperature, the higher the resistance. Below are averaged data for standard sensors used in technology Ariston.
| Temperature (°C) | Resistance (kOhm) | Permissible error | Condition |
|---|---|---|---|
| +25 °C | 4.7 - 5.2 kOhm | ± 5% | Normal (room) |
| +10 °C | 8.5 - 9.0 kOhm | ± 10% | Normal (cooling) |
| 0 °C | 12.0 - 13.5 kOhm | ± 10% | Freezing limit |
| -18 °C | 28.0 - 32.0 kOhm | ± 15% | Normal (freezing) |
If your measurements differ significantly from the table values, for example, at +25°C the device shows 2 kOhm or 15 kOhm, this is a direct indication of the degradation sensitive element. Such a sensor will transmit distorted data to the control module, which will lead to incorrect operation of the entire unit.
Frequent errors during diagnostics and replacement
One of the most common errors is an attempt to “ring” the sensor without disconnecting it from the board. As already mentioned, this can lead to the failure of an expensive electronic module. Always check that the sensor connector is disconnected from the main board or wiring harness before touching probes.
Another mistake is ignoring the wiring condition. Often the thermistor itself is intact, but the wire is frayed or oxidized at the soldering site. The visual inspection must be thorough. Check the wires from the connector to the sensor itself for breaks. Insulation integrity Also important, especially in the evaporator area where humidity is possible.
- ❌ Ignoring tightness: When installing a new sensor, it is important to ensure a tight connection, otherwise moisture will cause corrosion.
- ❌ Incorrect rating: Installing a sensor with a different resistance will lead to incorrect operation of the refrigerator.
- ❌ Rough installation: A wire jam during assembly can lead to repeated failure in a month.
⚠️ Attention: Technical characteristics and location of parts may vary slightly depending on the specific modification of the Ariston refrigerator. Always check the service documentation for your model.
FAQ: Frequently Asked Questions
Is it possible to temporarily short-circuit the sensor to make the refrigerator work?
Theoretically, shorting the sensor (resistance 0 ohms) will cause the module to think that the temperature is extremely low and the compressor will shut down. An open circuit (infinite resistance) can cause it to run continuously. However, these are emergency measures that may result in food defrosting or compressor failure due to continuous operation. You cannot use a refrigerator with a shorted sensor.
Where to buy an original sensor for Ariston?
It is best to look for original spare parts in authorized service centers or specialized stores of spare parts for household appliances. When purchasing, pay attention to the markings and resistance. Universal sensors may not be suitable in size or characteristics.
Why does the error not disappear after replacing the sensor?
In some models Ariston it is necessary to reset the error through the menu or completely de-energize the refrigerator for 15-20 minutes. If the error persists, the control board itself may be faulty or the wiring connecting the sensor to the module is damaged.
How to understand that the sensor is lying, but has not completely burned out?
This requires a test with a change in temperature. Place the sensor in the refrigerator (on a shelf, not in the freezer) for 15 minutes. Resistance must grow. If it remains the same or has changed slightly, the sensitivity of the element is impaired and it needs to be replaced.