Sudden cessation of operation of the refrigeration chamber or, conversely, excessive formation of ice often indicates a failure in the temperature control system. Temperature sensor is one of the key elements responsible for the stability of the microclimate inside the unit. If it fails or transmits incorrect data to the electronic module, the compressor may run continuously or not turn on at all, which leads to food spoilage.
Understanding where this element is physically located is necessary not only to replace it, but also to correctly diagnose faults. The location of the sensor directly depends on the type of cooling system - be it a classic “crying” system or a modern one. In this article, we will analyze in detail the design features of various models and help you accurately determine the location of the sensitive element in your device. No Frost. In this article, we will examine in detail the design features of various models and help you accurately determine the location of the sensitive element in your device.
It is worth noting that independent intervention in the design requires caution and compliance with safety precautions. Before starting any work, be sure to disconnect the refrigerator from the power supply to avoid electric shock or damage to the electronics.
Principle of operation and types of temperature sensors
Before looking for the physical location of the element, it is important to understand what exactly we are looking for. Modern refrigerators use two main types of control devices: mechanical thermostats and electronic thermistors (thermistors). Mechanical thermostat is a sealed capsule with gas or liquid connected to a bellows that opens or closes the electrical circuit when the volume of the working fluid changes.
Electronic sensors, most often found in models with the system No Frost and digital control, are thermistors. Their resistance changes depending on the ambient temperature, which allows the electronic module to regulate the operation of the compressor and fans with high precision. Such elements are usually smaller in size and are mounted directly on the evaporator or in the air duct.
⚠️ Attention: Attempting to replace a mechanical thermostat with an electronic one (or vice versa) without reworking the entire refrigerator control system is impossible and will lead to equipment failure.
The accuracy of the sensor readings is critical to energy efficiency. If the sensor is lying, the refrigerator may consume 20-30% more electricity trying to achieve non-existent cold. Therefore, timely diagnostics and knowledge of the location of the element help save the budget.
Location of the sensor in refrigerators with a drip system
In classic models that use a drip defrosting system, the temperature sensor (thermostat) is most often located inside the refrigerator compartment. Its task is to read the air temperature directly in the chamber volume. Visually, you can detect a plastic regulator knob on the inner wall, but the sensitive element itself is hidden.
The sensitive part of the thermostat, called capillary tube, is usually mounted on the back wall of the chamber or built into a special channel. The tube can be hidden under a plastic panel or secured with clips next to the evaporator. In some Atlant or Indesit models, the end of the capillary can be immersed in a special hole in the bottom of the chamber or attached to the surface of the evaporator.
- 🔍 Look for a plastic adjustment knob on the ceiling or side wall of the chamber.
- 🔍 Inspect the back wall for plastic plugs or channels.
- 🔍 Check the space behind the removable shelves and drawers.
To access the sensor in such models, you often have to remove the top cover of the refrigerator (if the thermostat is built into the case) or dismantle the internal plastic panel of the rear wall. Be careful with plastic latches, they can become fragile after years of use.
Where to look for sensors in the No Frost system
Refrigerators with the system No Frost are more complex and require temperature control at several points. It is rare to find one single sensor here. Usually there are several of them: one controls the air temperature in the chamber, another controls the temperature of the evaporator to control defrost cycles, the third can monitor the temperature in the freezer.
The main one (defroster) is always attached directly to the evaporator. Since the evaporator on these models is hidden behind the back panel in the freezer (or behind the panel in the refrigerator, depending on the model), partial disassembly will be required to locate it. It looks like a small plastic cylinder or tablet pressed against the metal tubes of the evaporator. defrost sensor (defroster) is always attached directly to the evaporator. Since the evaporator on these models is hidden behind the back panel in the freezer (or behind the panel in the refrigerator, depending on the model), partial disassembly will be required to locate it. It looks like a small plastic cylinder or pellet pressed against the metal tubes of the evaporator.
The air sensor in the system No Frost is often hidden in the air duct or behind a decorative grille on the back wall. This is done so that it measures the temperature of the circulating air, and not the temperature of the products lying close to the wall.
⚠️ Attention: When defrosting the refrigerator No Frost to access the sensors, it is strictly forbidden to use sharp objects to chip ice or a hair dryer to speed up the process, since you can damage the thin evaporator tubes or the evaporator itself sensor.
In two-compressor models No Frost the set of sensors is doubled: a separate circuit for the freezer and a separate circuit for the refrigerator compartment. This increases reliability, but complicates diagnostics.
How many sensors can there be in a modern refrigerator?
In complex two-chamber models with a freshness zone and a display, the number of sensors can reach 4-5: the main one in the refrigeration chamber, the main one in the freezer, the evaporator defrost sensor, the sensor in the air supply channel and the sensor in the zero zone.
Fault diagnosis: how to understand that the sensor has failed
You can determine the malfunction thermal sensor by indirect signs, without immediately resorting to complex tools. If your refrigerator starts working abnormally, first analyze the symptoms. Users often confuse a sensor failure with a freon leak or a compressor malfunction.
The surest way to check is to use a multimeter. The sensor is removed from the circuit and its resistance is measured at different temperatures. To do this, you can place it in a container of water of known temperature (measured with a thermometer) and take ohmmeter readings.
Compare the data obtained with the table of nominal resistances for your model. The spread of values should not exceed the permissible standards specified in the technical documentation.
| Symptom | Possible cause (Sensor) | Action |
|---|---|---|
| The refrigerator does not turn off | Sensor “frozen” in the “warm” position | Checking resistance, replacing |
| The compressor does not turn on | The sensor shows “too cold” | Chain continuity, checking contacts |
| Frequent on/off cycles | Unstable sensor readings | Element replacement |
| Increasing “coat” of ice | Faulty defrost sensor | Checking the circuit defrosting |
If the resistance of the sensor is infinitely high (open) or zero (short circuit), the element must be replaced. Sometimes the contacts at the junction of the sensor with the wiring oxidize, so before buying a new part you should check the connectors.
☑️ Checklist before buying a new sensor
Instructions for replacing the temperature sensor
The process of replacing the temperature sensor varies depending on the model, but the general algorithm of actions remains similar. The main rule is safety and accuracy. Do not allow moisture to get on the electronic boards during operation.
First you need to ensure access to the installation site. For refrigerators No Frost this means removing the back panel in the freezer compartment. Be prepared for the fact that there may be ice that will have to be defrosted naturally within several hours.
- 🛠 Unplug the refrigerator and defrost the chamber.
- 🛠 Remove shelves, drawers and protective plastic panels.
- 🛠 Find the sensor, disconnect the connector and remove the fastening clips.
- 🛠 Install the new sensor, observing the polarity (if the connector is not symmetrical).
After installing the new element, reassemble the structure in the reverse order. Turn on the refrigerator and let it work without loading food for several hours so that the system returns to normal mode.
In mechanical thermostats, replacement may require adjusting the length of the capillary tube. It should not be bent or shortened too much, as this will break the tightness of the system and lead to failure of the new thermostat.
Nuances for popular brands
Different manufacturers use their own engineering solutions for placement temperature controllers. Knowing these features can save you time when searching.
In refrigerators Liebherr i Bosch sensors are often mounted in a special channel in the rear wall of the refrigerator compartment, access to which opens after removing the decorative duct cover. In models Samsung and LG with the system Twin Cooling sensors can be hidden deep in the housing behind the rear panel, and access to them sometimes requires removing the entire rear casing of the unit.
⚠️ Attention: Design features may change even within one model line depending on the year of manufacture. Always check the service documentation for a specific modification.
In domestic models "Biryusa" or "Don" the classic scheme with a TAM thermostat is often used, which is mounted on a bracket inside the chamber, and the capillary tube is placed behind the wall. This simplifies replacement, since it does not require complex disassembly of the evaporator.
Is it possible to temporarily dispense with the sensor?
Theoretically, some craftsmen close the defrost sensor circuit with a jumper for an emergency start, but this will lead to freezing of the evaporator in 1-2 days and possible failure of the compressor due to water hammer. This is not a solution to the problem, but a path to expensive repairs.
Frequently asked questions (FAQ)
Is it possible to replace a temperature sensor with a universal analogue?
Yes, in many cases you can use a universal thermistor if its resistance (for example, 5 kOhm or 10 kOhm at 25°C) is the same as the original. However, the length of the cable and the type of connector may differ, which will require soldering and extension of wires.
Why does the refrigerator freeze, but does not turn off after replacing the sensor?
Perhaps a sensor with the wrong resistance value is installed, or the problem lies not in the sensor, but in the compressor relay or refrigerant leak. It is also worth checking the tightness of the door.
How to check the sensor without a multimeter?
It is impossible to check accurately without instruments. An indirect method is to put the sensor in the freezer for 15 minutes, then quickly check the conductivity (if you have a simple tester with sound), but this method gives a large error.
Where is the sensor located in the freezer?
Usually it is attached to the evaporator (behind the back wall of the chamber) or built into the air duct coming from freezers into the refrigerator compartment. The exact location depends on the design of the specific model.