A modern refrigerator is a complex electronic a device where each element is responsible for the safety of your products. When the equipment stops freezing correctly or starts working in increased mode, it is often the culprit. Understanding where it is located is the first step to diagnosing the malfunction, which you can do yourself without calling a technician. temperature sensor. Understanding where it is is the first step to diagnosing the problem, which you can do yourself without calling a technician.
In this article we will analyze in detail the architecture of temperature control, consider the location of sensors in various types of refrigerators and explain how to distinguish sensor failure from other failures. You will learn why Indesit and LG hide these elements differently and what to look for during a visual inspection.
Before disassembling the equipment, it is important to understand the basic principle: the sensor does not control the motor directly, it only sends a signal to the electronic control module. Thermal sensor is The “eye” of the system, which reports whether the set temperature has been reached. If this “eye” is blind or sees incorrectly, the refrigerator begins to work chaotically, which can lead to food spoilage or icing of the evaporator.
Principle of operation and types of temperature sensors
The main element of the control system is thermistor. Its electrical resistance changes depending on the ambient temperature. The electronic board reads these changes and, comparing them with specified algorithms, makes a decision: turn on the compressor, start defrosting or activate the fan. Unlike old mechanical thermostats, modern sensors are highly accurate, but also more sensitive to voltage changes.
In modern models with the system No Frost up to four or more sensors can be used. They control different areas: the main chamber, the freezer compartment, the evaporator and even the incoming air. If one of them fails, the system may go into emergency mode, blocking normal operation of the compressor.
⚠️ Attention: Electronic sensors are very sensitive to static electricity. If you touch the contacts with your hands without antistatic gloves, you can damage the sensitive element, even if it looks intact on the outside.
There are two main types of sensors used in household appliances. The first type is classic NTC thermistors, the resistance of which drops when heated. The second type is more complex sensors with digital data transmission, which are often found in premium models Bosch or Siemens. Understanding the type of your device will help you choose the right replacement.
The location of the sensor in single-chamber refrigerators
In classic single-chamber models, the search thermal sensor usually does not cause difficulties. Most often it is integrated directly into the thermostat housing or located next to it. If you have an old-style refrigerator with a mechanical adjustment knob inside the chamber, the sensor (capillary tube) is located behind the plastic panel to which the handle is attached.
In models with electronic control, the sensor is often hidden in the upper part of the refrigerator compartment. It can be closed with a decorative plug or located inside the lampshade. To access it, it is sometimes necessary to remove the top shelf or dismantle the ceiling panel. In some cases, for example in models Stinol, the sensor may be hidden in a niche behind the back wall.
- 🔍 At the top of the camera, hidden behind a plastic cover.
- 🔍 Inside the thermostat housing (for mechanical models).
- 🔍 Nearby with a lampshade.
- 🔍 Behind the back wall in a special technological hole.
If you cannot find the sensor visually, refer to the diagram of your device. The design may vary depending on the year of manufacture. For example, in older models Atlant access to the sensor is easier, since the layout is less dense than in modern “Asian” assemblies.
Where to look for sensors in No Frost systems
Refrigerators with the system No Frost have a more complex architecture. Here defrost sensor plays a critical role. It is located directly on the evaporator, which is hidden behind the back wall of the freezer. If this element does not “see” the heating of the heating elements, the defrost cycle will not complete, and the evaporator will become covered with ice, blocking the air circulation channels.
To access the evaporator sensor, in most cases you will have to remove the back panel inside the freezer. This requires defrosting the chamber for 24 hours so that the ice does not damage the plastic fasteners during dismantling. The sensor is usually fixed in a special hole on the fins of the evaporator or inserted into a metal sleeve.
In addition, the system No Frost often contains a “crying” evaporator sensor or a sensor that controls the temperature of the outlet air. They can be located:
- ❄️ On the aluminum fins of the main evaporator.
- ❄️ In the air duct between the chambers.
- ❄️ In the blower fan area.
- ❄️ In the bottom parts of the freezer compartment (to control water flow).
It is important to understand that in two-chamber refrigerators LG or Samsung s No Frost sensors are often filled with sealant or tightly pressed with metal brackets. Replacing them requires care so as not to damage the fragile evaporator tubes.
Why does the defrost sensor fail more often than others?
It works in extreme conditions, constantly experiencing changes from -20°C to +10°C during defrost cycles. Thermal fatigue of the material leads to a change in resistance and loss of accuracy.
Specific placement in two-chamber models
In two-chamber refrigerators, where the freezer and refrigerator compartment are separated, the sensors are distributed between both zones. In the refrigerator compartment, a sensor typically monitors the overall air temperature to prevent food from freezing. In the freezer, the task is to prevent deep-frozen defrosting. Thermal sensor in the freezer compartment it is often located in the upper third, since cold air is heavier and sinks down.
In models with a “zero temperature” or “fresh zone” zone, additional ones can be installed independent sensors. They allow you to maintain a temperature of about 0°C with an accuracy of a degree. The location of such sensors is individual for each model and is often indicated in the service manual.
For clarity, here is a table of the location of the main sensors in popular brands:
| Brand | Refrigerator compartment | Freezer camera | Features |
|---|---|---|---|
| Indesit | Behind the back wall or in the lampshade | On the evaporator (behind the panel) | One sensor per camera is often used |
| Bosch | In the upper part, under decor | Built into the control unit or on the evaporator | High precision, complex circuits |
| LG | On the side or in the ceiling of the chamber | On the fins of the evaporator | Many sensors in the system No Frost |
| Atlant | Next to the thermostat | In the cold supply channel | Available design for repair |
When troubleshooting a two-chamber refrigerator, pay attention to the error code on the display. It often indicates not just a “sensor error,” but specifically “evaporator sensor” or “fridge compartment sensor,” which narrows the search.
Fault symptoms and diagnostics
How to understand what thermal sensor is it acting up even before opening the case? The most obvious sign is that the refrigerator runs non-stop or, conversely, turns on too rarely. If food in the refrigerator compartment begins to freeze and melts in the freezer, this is a sure sign that the system is receiving incorrect temperature data.
Another symptom is frequent turning on and off of the compressor (clocking). This happens when the sensor “jumps” in readings, either reporting overheating or hypothermia. In models with a display, the alarm indication may light up or the temperature icon may flash.
⚠️ Attention: If the refrigerator makes loud relay clicks, but the compressor does not start, the problem may not be in the sensor, but in the start relay or the compressor itself. Do not change serviceable sensors without first checking them.
Required for accurate diagnostics multimeter. You need to remove the sensor, bring it to room temperature (or immerse it in water of a known temperature) and measure the resistance. The readings must correspond to the resistance table for the specific model. If the resistance is infinite (open circuit) or equal to zero (short circuit), the element is faulty.
☑️ Sensor diagnostics
Replacement process and important nuances
Replacement thermal sensor is a procedure accessible to a person with basic repair skills. The main rule: all work is carried out only with the device disconnected from the network. After dismantling the old element, the new one is installed in the same seat. It is important to ensure tight contact of the sensor with the surface that it must monitor.
Often new sensors are supplied with a universal connector or without it at all. In this case, you have to rearrange the chip from the old sensor. To do this, the wires are carefully stripped and twisted, making sure to insulate the junction with heat shrink or high-quality electrical tape. Moisture is the main enemy of electrical connections in a refrigerator.
After installing and assembling the refrigerator, do not rush to load food. Let the equipment run idle for 2-3 hours. This will allow the control module to calibrate and reach the correct temperature. If no errors have occurred during this time and the temperature has stabilized, the repair can be considered successful.
Common mistakes during self-repair
One of the common mistakes is installing the sensor "on eye" without fixation. If the sensor is not pressed tightly against the evaporator or wall, it will show the air temperature rather than the surface temperature, which will lead to incorrect defrost cycles. In systems No Frost this is fraught with rapid accumulation of ice.
Also, novice craftsmen often ignore the length of the wire. You can extend the sensor wire, but only using a wire of the same cross-section and type. Using a wire that is too thin can introduce additional resistance and distort the readings, which the electronics will perceive as an error.
Remember that not all sensors are interchangeable. Even if the connector physically fits, the resistance characteristics may vary. Installing the wrong one thermistor will cause the refrigerator to work, but not in optimal mode, consuming more electricity.
Is it possible to temporarily short-circuit the sensor to make the refrigerator work?
Technically, if you short-circuit some types sensors (depending on the logic of the board), the refrigerator can switch to constant compressor operation mode. However, this is an emergency measure that will lead to freezing of food and possible failure of the compressor due to the lack of rest cycles. This method can only be used for short-term diagnostics.
Why does the refrigerator beep after replacing the sensor?
Most likely, the new sensor has a different resistance, and the control module “sees” the discrepancy. Either the cable was damaged during replacement, or the chip was not fully inserted into the connector. There may also be a failure in the module memory, which sometimes requires a reset (disconnection from the network for 15-20 minutes).
Where to buy an original temperature sensor?
It is best to look for original spare parts by catalog number (part number) in specialized stores of spare parts for household appliances or from official dealers of the brand. There are many universal analogues on the market that are suitable in size, but may differ in temperature curve.
Does ice adhering to it affect the operation of the sensor?
Yes, the ice crust on the sensor, especially on the defrost sensor, acts as an insulator. It stops feeling the heat of the heating element, and the defrosting cycle is interrupted prematurely or does not start at all. Regular defrosting of the refrigerator helps to avoid this problem.