Sudden defrosting of the freezer or, conversely, food turning into an ice ball in the refrigerator compartment are sure signs that thermostat has failed. In two-chamber models of the brand Atlant this unit is responsible for maintaining the set temperature, opening the compressor power circuit when the desired cold is reached. If the refrigerator starts working without interruptions or turns on extremely rarely, ignoring the settings of the regulator knob, most often the problem lies precisely in the temperature sensor.
Independent replacing the thermostat does not require complex equipment and is available to any home craftsman who is ready for careful work with electrics. The main difficulty lies in correct access to the unit, which for different series Atlant can be located differently: either under the top cover of the refrigerator compartment, or behind the decorative panel inside. Before starting work, it is critically important to completely disconnect the device from the power supply, since you have to work with live parts under a voltage of 220 volts.
The success of the repair depends on diagnostic accuracy and correct selection of an analogue, because the design of the bellows tube and the length of the capillary may differ for different models. In this article we will analyze the algorithm of actions, help determine the type of malfunction and describe in detail the process of dismantling the old one and installing a new one thermostat. Compliance with the sequence of operations will allow you to restore the operation of the unit without calling a technician.
Principle of operation and signs of malfunction of the thermostat
Thermostat (thermostat) in refrigerators Atlant is an electromechanical device that controls evaporator temperature. Inside the housing there is a sealed bellows tube filled with freon or refrigerant with similar properties. As the temperature drops, the pressure in the tube drops, the contacts open and the compressor stops. As the temperature rises, the pressure increases, the membrane straightens and closes the contacts, starting a cooling cycle.
Understanding this mechanism helps to identify a breakdown. If your refrigerator Atlant stops turning off and works “non-stop”, freezing like a “fur coat” even in the summer, this is a classic symptom of contacts sticking in the closed position. The compressor is humming, the condenser (grid at the back) is hot, but the cyclic operation is broken. In this case thermostat does not feel that the required temperature has already been reached.
⚠️ Attention: If the refrigerator, on the contrary, is silent for days, and the food in the refrigerator compartment is warm, although it is still cold in the freezer, this may indicate an open circuit inside the thermostat or loss of tightness of the bellows tube.
Another sign of a malfunction is an incorrect response to turning the adjustment knob. In good condition, when turning the regulator to minimum, a characteristic click of the contacts opening should be heard, and the engine should stop. If there is no click, or the refrigerator continues to work even at the minimum setting, temperature sensor requires replacement. You should also be wary if the operating intervals have become chaotic and do not correspond to the set values.
It is important not to confuse a thermostat breakdown with a freon leak or a compressor malfunction. If the engine hums, tries to start, clicks the relay, but immediately stalls, the problem is most likely in the start-up relay or the engine itself, and not in the regulator. The thermostat is responsible only for the logic of turning on and off, but not for the mechanical start of the rotor.
Diagnostics and selection of a new thermostat
Before buying a new part, you need to make sure it is faulty and remove the old sample for comparison. In two-chamber refrigerators Atlant manufactured thermostats Tam, K-59, K-50 or domestic TAM-133are most often used. The numbers in the marking indicate the length of the capillary tube and the type of rod. For example, Tam 133-1M is an analogue of K-59, which is the most common option for the refrigeration chamber.
For a visual check, remove the regulator handle and the plastic cover. Often the thermostat housing itself is visible underneath them. If traces of melting, oxidation of contacts or mechanical damage to the insulation are visible on the case, replacement is required. However, external integrity does not guarantee the integrity of the internal electrical system. The most reliable way to check is to “test” with a multimeter in resistance measurement mode.
- 🔍 Disconnect the refrigerator from the mains and remove the wires from the thermostat contacts (after photographing the circuit).
- 🔍 Unscrew the thermostat from its seat, being careful not to damage the capillary tube.
- 🔍 Connect the multimeter probes to the contacts: at room temperature the resistance should be close to zero (the circuit is closed).
- 🔍 Place the sensitive part (bellows) in a container with cold water (about 0...+5°C) - the circuit should break and the device will show infinity.
If the multimeter shows a break at room temperature or, conversely, a short circuit even after cooling, the part is faulty. When buying a new thermostat pay attention to the length of the capillary tube. It can vary from 0.73 m to 2.5 m. For most two-chamber Atlantov top freezers, a length of about 0.73–1.3 meters is suitable. A tube that is too long can be carefully rolled into a ring inside the chamber, but a short one cannot be extended.
Is it possible to use a thermostat with a different marking?
The use of analogues is possible if the electrical parameters and the type of rod mounting are the same. However, the length of the capillary tube is critical: if it is too short, the refrigerator will not turn off, since the tube will not reach the desired temperature zone. If it is too long, you will have to carefully lay it, avoiding kinks.
Necessary tools and preparation for work
Refrigerator repair Atlant do-it-yourself requires a minimum set of tools, but their presence is mandatory for safe and high-quality work. The main task is to provide access to the node and carefully switch the wires. Do not try to carry out repairs “by eye” or using improvised means such as a knife instead of a screwdriver, this can lead to damage to the plastic elements of the case.
You will need the following tools and materials:
- 🔧 Phillips and flat-head screwdrivers (for dismantling panels and terminals).
- 🔧 Multimeter (for checking the circuit).
- 🔧 Pliers or pliers (for removing the tube).
- 🔧 Insulating tape or heat shrink (for insulating connections).
- 🔧 Flashlight (for illuminating the interior space).
Preparation of the unit begins with complete defrosting. Even if you are only replacing electrical components, the presence of ice can make it difficult to access the fasteners or accidentally damage the capillary tube of the new thermostat during installation. Leave the refrigerator turned off for at least 12 to 24 hours. It is also necessary to move the unit away from the wall to provide easy access to the rear if the compressor needs to be checked, although this is rarely necessary to replace the thermostat.
⚠️ Caution: The thermostat capillary tube is made of thin copper and is easily deformed. Any bend or crease will lead to rupture and leakage of the filler gas, which will make the new thermostat inoperative immediately after installation.
Prepare the workplace in advance. You will need a table or cabinet next to the refrigerator, where you can put the removed shelves, drawers and itself thermostat. Having a smartphone handy to take photos at each stage of disassembly is the best way to avoid getting tangled in wires during reassembly. Pay special attention to cleanliness: dirt and moisture inside the electrical unit are unacceptable.
☑️ Preparing to replace the thermostat
Removing the old thermostat in the Atlant refrigerator
The process of removing a faulty unit in two-chamber models Atlant has its own characteristics. In most series (for example MHM-1700, 1800, 2800), the thermostat is located in the upper right corner of the refrigerator compartment. Access to it is blocked by a decorative overlay or cover of the lighting lamp. In some models, especially with the No Frost system, access can be through the control panel on top.
The dismantling algorithm is as follows:
- Remove the temperature control knob. It simply pulls towards itself, sometimes a slight rocking is required.
- Remove the plastic cover (visor) under which the thermostat is hidden. It can be secured with latches or screws.
- Remove the lampshade (if it interferes with access) by unscrewing the screw or releasing the clamps.
- Carefully remove the bellows tube from the hole in the chamber wall. It is usually inserted into a plastic casing or channel.
Once you gain access to the electrical part, you will see the thermostat housing with the appropriate wires. Before disconnecting, be sure to take a photo or draw a wiring diagram for the wire colors. In Atlantakh standard colors are often used: white, black, red, yellow with a green stripe (grounding), but it is better to double-check visually. Disconnect the block or remove the wires from the terminals using a flat-head screwdriver to press out the fasteners.
Next you need to unscrew the thermostat itself from its seat. It is held on by a nut or screws. Be careful when pulling out the housing to ensure that the tube does not get caught on any sharp edges of metal or plastic. Pull the knot smoothly, straightening the tube. If the tube goes deep into the thermal insulation, do not pull with force - find the exit point and work carefully.
Installation of a new thermostat and connection diagram
Installation of a new one thermostat is carried out in the reverse order of dismantling, but observing important nuances. First, insert the sensing tube into the wall channel of the refrigerator compartment. Push it carefully, without jerking, to the full depth that the old tube allowed. The end of the tube should be in the area where the sensitive element was previously located, usually this is the area near the evaporator.
Fix the thermostat body in the seat by tightening the fixing nut. Now we move on to the most important stage - the electrical connection. If you did not photograph the wires, use the universal diagram for thermostats K-59 / Tam 133which are most often installed in Atlanta.
| Contact number | Wire color (standard) | Purpose | Where to connect |
|---|---|---|---|
| 3 | Red | Phase input (network) | From power cable / relay |
| 4 | Black | Output to compressor | To motor start relay |
| 6 | Yellow | Ground | To housing (if any) |
| - | White/Orange | Light Bulb | To Door Switch/Lamp |
It is important to understand that the wire colors in your specific refrigerator Atlant may vary from factory standards, especially if the wiring was redone earlier. Therefore, rely on logic: the wire coming from the network (via the relay) should go to the thermostat input, and the wire going to the compressor should go to the output. The lamp wires are usually connected in parallel and are interrupted by the door switch, not the thermostat, but in some circuits they can pass through the contacts of the regulator.
After connecting all the wires, check the reliability of the contacts. They should fit tightly and not wobble. If terminal blocks are used, make sure they snap into place. Insulate all exposed live parts, even if they are inside a plastic housing, to eliminate the risk of short circuits due to vibration.
Setup and first start after replacement
After installing all the plastic panels, the regulator knob and returning the refrigerator to its place, you can begin testing. Plug in the unit. In the first minutes, you can hear a characteristic click - this is the contacts of the thermostat closed, and current flows to the engine. The compressor should start in a few seconds (or immediately, depending on the relay model).
Set the control knob to the middle position (usually number 3 or 4 out of 7). Let the refrigerator run for several hours. It is better to do the first loading with products gradually, so as not to create a sudden heat load. Follow the cyclic operation: the refrigerator should gain temperature, turn off, stand for a while and turn on again.
- ❄️ If the refrigerator runs non-stop for more than 2 hours and does not turn off, the capillary tube may not be immersed deep enough in the chamber or the thermostat is defective.
- ❄️ If the unit turns off after 5-10 minutes and does not turn on for a long time, but it is warm inside, perhaps the tube is pinched or the contacts do not close.
- ❄️ If the temperature in the refrigerator compartment is normal (+4...+6°C), and the freezer is not cold enough, the position of the tube may need to be adjusted closer to the evaporator.
A final assessment of the quality of the replacement can be given through 24 hours of work. During this time, the temperature regime stabilizes. If you notice that an excessive “fur coat” is forming on the back wall of the refrigerator compartment or, conversely, that food is melting, try adjusting the position with the handle. If adjustment does not help, you may need to re-check the capillary tube installation.
⚠️ Attention: Thermostat specifications may vary slightly from batch to batch. If, after replacement, the operating mode of the refrigerator seems incorrect to you (too long pauses or too frequent switching on), check the product data sheet or consult with a specialist, as the switching differential may need to be adjusted.
Frequently asked questions (FAQ)
Is it possible to temporarily short-circuit the thermostat wires to make the refrigerator work?
Technically, it is possible to connect the wires going to the compressor, bypassing the thermostat. The refrigerator will start working and will freeze constantly. However, this is an emergency mode: the compressor will work non-stop, which will lead to freezing of the evaporator, overloading the engine and high energy consumption. You can use this method only for a short time (several hours) to save food until a new part arrives.
Why does the new thermostat click, but the compressor does not start?
If you hear a clicking of the contacts, but there is no hum from the motor, the problem is not in the thermostat. Most likely, the compressor start-up relay is faulty, the compressor itself is faulty (turn-to-turn short circuit or wedge) or there is an open circuit in the power supply circuit. Also check whether the wires are tightly seated in the terminals.
Do you need to bleed gas from the old thermostat before disposal?
Inside the thermostat bellows tube there is a small amount of refrigerant (freon or similar) under low pressure. When the tube is punctured or cut, the gas will simply escape. There is no need to specially release it, but it is not recommended to inhale the vapors. Dispose of the part as electronic scrap.
Is a thermostat from another refrigerator suitable, for example, from Indesit or Stinol?
Many thermostats are unified. If the marking (for example, K-59, L-50) and the length of the capillary tube match, and the type of rod (grooved or smooth) also matches, then installation is possible. However, the seats and shape of the body may differ between brands, which will require a “collective farm” with fasteners, which is undesirable.