Thermostat malfunction in refrigerators Atlant is one of the most common causes of temperature violations. If you notice that the chamber freezes too much or, conversely, the food has begun to spoil, and the compressor works without interruption or does not turn on at all, the problem may lie in this small device. The thermostat (or thermostat) is responsible for controlling the temperature inside the chambers and sends a signal to turn the engine on or off.
In this article we will look in detail at how to independently determine what has failed exactly thermostat, and we will check it using a multimeter. It is important to understand that diagnostics require care and compliance with safety measures, since the work is carried out with electrical components. Before you begin disassembling, make sure that you have basic skills in working with electrical appliances.
Refrigerators Atlant are equipped with different types of thermostats, and the methodology for checking them may differ slightly. However, the general principle of operation remains the same for all models: opening and closing contacts depending on the temperature of the sensitive element. If you doubt your abilities, it is better to contact a specialist, but if you decide to act on your own, follow our instructions step by step.
Main signs of a thermostat malfunction
Before disassembling the unit, you need to analyze its behavior. Symptoms Thermostat breakdowns are common confused with a freon leak or a compressor malfunction, but there are characteristic differences. First of all, pay attention to the operating mode of the motor-compressor. If it hums continuously, without stopping to rest, or, conversely, is silent for hours, although it is warm in the chamber, this is the first alarm bell.
Another obvious sign is the formation of an excessive amount of ice or, conversely, the complete absence of cold when the compressor is running. In models with mechanical control, the regulator knob can scroll without characteristic clicks, which indicates mechanical destruction of the internal mechanism. It is also worth listening: if when you turn the temperature adjustment knob you do not hear a click, and the compressor does not respond, the circuit most likely does not close.
- 🔊 The compressor works without stopping or does not turn on at all.
- ❄️ A “coat” of ice or food is formed in the refrigerator compartment are defrosted.
- 🔄 The thermostat knob scrolls freely, without fixing the positions.
- ⚡ There is no characteristic click when turning the regulator.
It is worth noting that in two-chamber models Atlant with the No Frost or drip system defrosting, the symptoms may be similar, but the causes may be different. For example, if only one chamber is not working, the problem may be a clogged capillary tube rather than a clogged thermostat. However, if the refrigerator behaves completely inappropriately, the probability of failure temperature sensor or the mechanical regulator is very high.
⚠️ Attention: If you find that the thermostat housing is melted or blackened, this indicates a short circuit or overload networks. In this case, simply replacing the part may not help - you need to check the wiring and the start relay.
Thermostat location in different Atlant models
The search for a thermostat depends on the specific series of your refrigerator Atlant. In older models and most modern two-compartment units with mechanical controls, the thermostat is usually hidden inside the refrigerator compartment. To get to it, you often need to remove the lighting cover or dismantle the plastic cover on the back wall.
In models with electronic control, the situation is different: there the role of a mechanical thermostat is performed by thermal sensors (thermistors), which are located at different points of the chambers. They are checked differently, by measuring the resistance, and not by checking the contacts. Mechanical regulators, such as T-133, TAM-133 or K-59, have a capillary tube that goes into the evaporator.
To access the mechanical thermostat in most cases, the algorithm of actions is as follows:
- 🔌 Disconnect the refrigerator from the power supply.
- 🧊 Empty the refrigerator compartment from food.
- 🔩 Remove the temperature control knob (pull it towards you).
- 🔍 Remove the decorative panel or lamp shade.
Sometimes the thermostat may be hidden behind the control panel located outside at the top of the refrigerator. In such models Atlant you must carefully snap off the plastic cover of the control unit. Be careful with plastic latches, they can be fragile, especially if the refrigerator has been in use for a long time.
Where to look for the capillary tube?
The thermostat capillary tube is usually attached to the evaporator inside the chamber or in the foamed part of the case. Do not damage it when dismantling, otherwise the refrigerant will come out.
Removing the thermostat for inspection
After you have reached the unit, it must be removed for visual inspection and further diagnostics. The thermostat is usually secured with one or two screws, or with special brackets. Before unscrewing, be sure to take a photo of the wire connection diagram so that you do not mix up the contacts during assembly.
Carefully disconnect the terminals. If the contacts are oxidized, they can be cleaned, but if the goal is to check integrity, it is better to immediately proceed to tests. The capillary tube must be removed extremely carefully: it is thin and easily pinched. In some models Atlant the tube is simply inserted into a hole in the chamber wall, in others it is glued or pressed with a bar.
When removing, pay attention to the condition of the wire insulation. If the braid is cracked or melted, this may cause unstable operation. Also check for signs of corrosion on the thermostat housing itself. The presence of moisture inside the thermostat housing is a sign of a seal failure, and such a part must only be replaced.
☑️ Removal checklist
Checking the thermostat with a multimeter
The most reliable diagnostic method is to “test” the contacts with a multimeter. To do this, switch the device to resistance measurement mode (Ohm) or continuity mode. If you do not have a multimeter, you can use a test lamp connected to a battery, but a multimeter gives a more accurate result.
Connect the multimeter probes to the thermostat contacts. In normal condition (at room temperature), the contacts should be closed and the device will display zero or emit a beep. If the device shows “infinity” (one on the screen), then the circuit is broken and the thermostat is not working. However, this is not yet a final diagnosis.
Next, you need to check the thermostat's response to temperature changes. To do this, immerse the sensitive capillary tube (about 5 cm) in a container with cold water (temperature about +5...+10°C) or, conversely, heat it, depending on the type of contacts. For most household thermostats Atlant when cooling, the contacts should open (if it is a normally closed contact) or close. The exact type of contacts (normally open or normally closed) depends on the marking:
| Marking | Type of contacts | Cooling behavior | Application |
|---|---|---|---|
| T-133, TAM-133 | Normally closed | Open | Refrigerator compartment |
| T-145, TAM-145 | Normally open | Closed | Freezer compartment (No Frost) |
| K-59 | Normally closed | Open | Universal |
| T-110 | Normally closed | Open | Single-chamber refrigerators |
If, when the temperature of the capillary tube changes, the multimeter readings do not change (the contacts do not open and do not close), the thermostat is faulty. Also check the continuity of the contacts: the resistance should be close to zero. High resistance indicates burning of the contacts inside, which will lead to sparking and eventual breakdown of the compressor.
⚠️ Attention: Never test the thermostat under 220V voltage by simply connecting it to the network without load. This is life-threatening and may cause a short circuit. Use only a multimeter in dial mode.
Replacing and setting up a new thermostat
If diagnostics confirm a malfunction, the thermostat must be replaced. It is important to choose an analogue with identical parameters. For refrigerators Atlant most often, models of the series THERE or imported analogues Danfoss (K series) are used. Pay attention to the length of the capillary tube: it should not be shorter than the original, the excess length can be carefully twisted into a ring.
Installation is done in the reverse order. Attach the new thermostat, connect the wires according to the photograph taken earlier. Pay special attention to grounding: if there is a grounding terminal on the thermostat housing, it must be connected. After assembly, turn on the refrigerator and set the control knob to the middle position.
The first start may take some time. Allow the refrigerator to reach temperature. If after 30-40 minutes of operation the compressor does not turn off, adjustment may be required. On the housing of some thermostats there is an adjustment screw closed with a seal. It is not recommended to turn it without a pressure gauge kit, as you can reset the factory settings.
Frequently asked questions (FAQ)
Is it possible to repair the thermostat yourself?
Theoretically, you can try to disassemble the case and clean the contacts, but this is a temporary measure. The tightness of the bellows (capillary system) is broken when opened, and the thermostat stops responding correctly to temperature. A complete replacement of the unit is recommended.
Why doesn’t the new thermostat click?
Some modern thermostats operate silently or have a very quiet switching mechanism. If the refrigerator begins to freeze and turns off in a cycle, the absence of a loud click is not a sign of a malfunction.
How to distinguish a thermostat from an air sensor?
The thermostat (mechanical) has a long capillary tube and an adjustment knob. The air sensor (electronic) is a small “pill” or rod without a tube connected to an electronic module. In refrigerators Atlant with electronics there is no thermostat as such.
How much does it cost to replace a thermostat?
The cost of the part itself varies, but the work of a master usually costs more than the spare part. Self-replacement saves up to 50% of the total repair cost, since you only pay for a new part.