A sharp increase in temperature in the refrigerator compartment or, conversely, the formation of an ice coat on the back wall often indicates a malfunction of the control system. In most models of household appliances, it is thermostat responsible for maintaining the set temperature. If this unit fails, the compressor either stops turning on altogether or works without interruptions, which ultimately leads to spoilage of products and breakdown of the unit itself.
Before calling a technician or purchasing a new part, it is necessary to carry out proper diagnostics. Checking the thermostat in the refrigerator Atlant with your own hands is a very real task that requires a minimum set of tools and basic knowledge of electrical engineering. Understanding the operating principle of this element will allow you to save significant money on service.
However, it is worth remembering that working with electrical appliances requires compliance with safety precautions. Any manipulations with electrical circuits should only be carried out with the equipment completely disconnected from the network. In this article, we will analyze in detail the algorithm of actions that will help you accurately determine the cause of the malfunction.
The principle of operation and symptoms of a malfunction of the thermostat
A thermostat, or thermostat, is an electromechanical device that opens or closes an electrical circuit depending on the temperature of the sensitive element. In refrigerators Atlant capillary thermostats are most often used. Inside the sealed tube there is a gas, which changes its pressure when the temperature changes, affecting the membrane and the contact switch.
The main task of the part is to turn on the compressor when the temperature in the chamber rises above the set one, and turn it off when the lower threshold is reached. If this cycle is disrupted, the refrigerator stops performing its functions. Understanding exactly how it works mechanismis critical for correct diagnosis.
⚠️ Attention: If your refrigerator begins to freeze too much, turning vegetables into ice, or the food in the main chamber begins to spoil due to heat, these are the first signals of a failure in the system thermoregulation.
There are a number of characteristic symptoms indicating failure of this particular part. You should not ignore even minor deviations in the operation of the unit, as they can lead to more serious problems with the compressor.
- 🧊 The compressor works continuously, without turning off for rest, even if it is already very cold in the chamber.
- 🔥 The refrigerator is silent: the motor-compressor does not start at all, although the light inside is on.
- ❄️ Insufficient cooling is observed in the refrigerator compartment, despite the maximum position of the control knob.
- 💧 A “snow coat” or ice crust forms on the back wall, which does not disappear after defrosting.
It is important to distinguish thermostat failure from other faults, such as Freon leak or compressor failure. If the motor hums, tries to start, but clicks and stops, the problem may be in the start relay or the engine itself, and not in the temperature sensor.
Necessary tools and preparation for diagnostics
To conduct a quality test, you will need a minimum set of tools. The most important device is multimeter (or tester), which allows you to measure the resistance of the circuit. Without this device, diagnostics will be only tentative.
In addition, it is necessary to prepare screwdrivers for dismantling the panels and removing the thermostat casing. Some models Atlant may require a flathead and a Phillips screwdriver of different sizes. It would also be a good idea to have a container of hot water on hand to check the sensitivity of the element.
Before starting any work, be sure to disconnect the refrigerator from the electrical network. This safety requirement is mandatory since you will be working with conductive elements. Waiting 10-15 minutes after turning off will allow the capacitors to discharge and the refrigerant to stabilize.
☑️ Preparing to check the thermostat
The location of the thermostat depends on the model of your refrigerator. In most modern two-chamber models Atlant it is located inside the refrigerator compartment, and in older or single-chamber versions it can be located outside, on the back wall of the case.
Removing the thermostat in Atlant refrigerators
The process of removing the thermostat requires care, to avoid damaging the fragile capillary tube. If you damage the tube, gas will come out of it, and you will have to buy a new thermostat again, since such elements cannot be repaired.
If the thermostat is located inside the chamber, you need to remove the plastic cover covering the lamp shade or control unit. It is usually held in place by latches or screws. After removing the cover, you will see the regulator itself with a handle and outgoing wires.
To remove the device, follow these steps:
- 🔧 Carefully remove the temperature control knob by pulling it towards you (sometimes it is secured with a locking screw).
- 🔌 Take a photo or draw a wiring diagram so that you don’t mix up the contacts during assembly.
- 📏 Disconnect the wires from the thermostat terminals, having previously marked them with a marker.
- 🧊 Carefully pull the sensitive tube out of the evaporator, trying not to jerk it sharply.
⚠️ Attention: The capillary tube is very thin and breaks easily. Remove it with smooth movements, without jerking or excessive force.
In models where the thermostat is located outside, the process is simplified: just remove the back metal cover on the refrigerator body. There you will see a black box with matching wires. Unscrew the fasteners and remove the assembly for testing.
Methods for checking with a multimeter at home
The most reliable diagnostic method is to check the electrical conductivity of the contacts using a multimeter. To do this, switch the device to resistance measurement mode (Ohm) or “dialing” mode with a sound signal.
Connect the multimeter probes to the thermostat contacts. In normal condition (at room temperature), the contacts should be closed, and the device will show zero or a resistance value close to it, and also emit a sound signal. If the device shows one or infinity, the circuit is broken.
For a complete check, you need to simulate a change in temperature:
- Place the thermostat sensitive tube in a container with hot water (temperature about 40-50 degrees Celsius).
- After 2-3 minutes, the contacts should open, and the multimeter should show an open circuit (one on the screen).
- Then cool the tube (you can put it in the freezer or spray it with freezing spray).
- When it cools down, the contacts should close again and the multimeter will beep.
If the contacts do not open when heating, this means that the thermostat is stuck and the compressor will work constantly, freezing the food. If they do not close even when cooling, the refrigerator simply will not turn on.
Why is it important to check at different temperatures?
Checking only at room temperature does not give a 100% guarantee. The thermostat may ring when cold, but not open the circuit when heating, which will lead to continuous operation of the compressor and overheating.
It is also worth visually inspecting the contacts for oxidation or carbon deposits. Sometimes the problem lies not in the mechanism itself, but in poor contact at the junction of the wires.
Correspondence table for models and types of thermostats
When replacing, it is important to choose the right analogue. Thermostats for refrigerators Atlant may differ in the length of the capillary tube, temperature range of operation and mounting method. Using an unsuitable part will result in incorrect operation.
Below is a table with common types of thermostats used in various series of refrigerators:
| Atlant refrigerator model | Thermostat type (analog) | Tube length (cm) | Features |
|---|---|---|---|
| Atlant MKhM 1700, 1800 | TAM-133 (K-59) | 80-90 | Two-chamber, inside the chamber |
| Atlant MKhM 2808, 2819 | TAM-133 (K-59) | 90-100 | With No Frost system |
| Atlant KSh-256 (single-chamber) | TAM-112 (K-50) | 60-70 | External mount |
| Atlant MHM 4000 series | TAM-133 (K-59) | 100+ | Increased tube length |
Please note that the length of the tube is a critical parameter. If the new tube is shorter than the original, it may not reach the desired area in the evaporator and the refrigerator will not work correctly. A tube that is too long can be neatly laid in rings, but this requires caution.
If you are not sure about the model of your thermostat, it is best to remove the old part and go to the store with it for a visual comparison.
Replacement of the part and initial startup
After successful diagnosis and After purchasing a new part, you can begin installation. Installation is carried out in the reverse order of dismantling. The main thing is to correctly connect the wires to the terminals of the new thermostat.
Follow the diagram that you drew up or photographed earlier. Usually the wires are color coded, but you shouldn't rely on color alone, as previous craftsmen may have made changes. The sequence of connection to the contacts is important.
Installation steps:
- 🛠️ Install the new thermostat in place of the old one, securing it with screws or latches.
- 🔌 Connect the wires to the appropriate terminals, ensuring reliable contact.
- ❄️ Carefully insert the capillary tube into the evaporator hole to the same depth as the old one.
- 🔧 Install the regulator handle and the plastic cover in place.
After assembly, turn on the refrigerator. Notice the sound of the compressor starting. If everything is done correctly, the motor should start working, and after a while cold should appear in the chamber.
In the first hours of operation, monitor the cooling process. If the refrigerator reaches temperature and turns off, it means the replacement was successful. If the cycle is not interrupted, additional adjustments or checking for freon leaks may be required.
Common mistakes when doing DIY repairs
Home repairs are often fraught with risks, especially if the technician does not have enough experience. One of the most common mistakes is ignoring safety rules when working with electricity and refrigerants.
Many users try to “revive” an old thermostat by tapping it or heating it with an open fire. This is strictly forbidden. An open flame can melt plastic elements or damage the insulation, and mechanical stress will finish off an already worn mechanism.
⚠️ Attention: Never use an open flame to check or defrost the thermostat tube. This can lead to an explosion of refrigerant vapor inside the tube or a fire.
Another mistake is incorrect filling of the capillary tube. If during installation you bend the tube too much or pinch it, it will stop responding to temperature changes. The tube should lie freely, without tension.
They also often forget to check the condition of the wire insulation. If the insulation is broken, a short circuit is possible, which can damage not only the thermostat, but also the control board or compressor.
FAQ: Frequently Asked Questions
Is it possible to temporarily do without a thermostat?
Technically, you can close the contacts directly to make the refrigerator work permanently. However, this will lead to continuous operation of the compressor, freezing of the evaporator and possible failure of the motor due to overheating. This is an emergency measure only to save food for a short time.
Where is the thermostat in the Atlant refrigerator with No Frost?
In models with the No Frost system, the thermostat is often hidden behind a plastic panel inside the refrigerator compartment, next to the lampshade. It is more difficult to get to it, since partial disassembly of the internal space is required.
Why does the new thermostat click but does not turn on the compressor?
The wires may be incorrectly connected, the compressor start relay or the engine itself may be faulty. Also, the reason may be the lack of freon in the system, which is why the pressure sensor (if there is one) blocks the start.
How to understand that the thermostat is “lying”?
If the refrigerator turns off when the chamber is still warm, or turns on when the food is already frozen, it means that the thermostat calibration is broken. In this case, only replacing the part with a new one helps.
Is it necessary to evacuate the system when replacing the thermostat?
No, replacing the thermostat does not require opening the freon circuit, since the capillary tube is sealed and is not directly connected to the refrigerant circulation system. Evacuation is only needed when repairing leaks or replacing a compressor.