Sudden defrosting of food or, conversely, their transformation into an icy monolith is a sure sign that the temperature control system has failed. In refrigerators of the brand Biryusa, as in many other models with mechanical control, a thermostat (thermostat) is responsible for this process. This small device constantly monitors the temperature in the chamber and commands the compressor to turn on or off. If you notice that your unit works without interruptions or turns on too rarely, most likely the problem lies in this unit.
Independent replacing the thermostat - a task that is quite doable for a person with basic skills in handling tools, but it requires care and compliance with safety precautions. Incorrect installation can lead not only to compressor failure, but also to refrigerant leakage if the evaporator is damaged. In this article, we will analyze the algorithm of actions in detail, help you choose the right analogue part and avoid common mistakes when repairing household appliances.
Before you begin disassembling, you need to make sure you have the necessary tools and a spare part. Repairs cannot be rushed, especially when it comes to sealed circuits and electrical circuits. A correctly selected part and strict adherence to the instructions will allow your refrigerator to return Biryusa operability in a short time, saving the budget on calling a technician.
Diagnostics of a thermostat malfunction
The first step should always be an accurate diagnostics Symptoms indicating a thermostat failure may be similar to symptoms of a compressor failure or a freon leak. The main symptom is the lack of cyclical operation: the compressor either hums continuously without turning off, or is silent for hours until the food begins to deteriorate. It is also worth paying attention to the temperature of the case: if it is hot, but there is no cold, this is one scenario, but if the motor does not start at all, it is another.
For the initial check, you can use the exclusion method. Try turning the control knob to different positions. If, when turning to the extreme position (maximum cold), a characteristic click does not occur and the compressor does not start, there is a high probability of failure of the electrical part of the thermostat. However, the final diagnosis is made only after a visual inspection and “dialing” of the contacts with a tester.
There is a simple but effective test method, which is often used by service center technicians. It consists of closing contacts directly. If, when connecting the wires bypassing the regulator, the compressor starts confidently, then the problem is in the thermostat. This method allows you to quickly eliminate other possible causes of failure.
⚠️ Attention: Carry out all manipulations with electrical wires and components of the refrigerator only after completely disconnecting the device from the power supply! Electric shock can be fatal.
Diagnostics also includes checking the condition of the capillary tube. If it has visible damage, swelling or signs of corrosion at the point of attachment to the evaporator, the thermostat must be replaced, even if the electrical part is still intact. The mechanical integrity of the sensitive element is critical for correct operation.
Selection of an analogue and marking of the part
Refrigerators Biryusa are equipped with various models of thermostats depending on the year of manufacture and the specific modification of the unit. The most common devices are domestically produced TAM, as well as imported analogs from Danfoss, Ranco or K59. The key parameter when selecting is not only the appearance, but also the temperature range, as well as the length of the capillary tube.
When looking for a replacement, it is important to pay attention to the markings on the body of the old part. The numbers and letters in the model code indicate the type of refrigerant, temperature mode and the presence of additional functions. For example, the presence of the letter “L” in the marking may mean protection against engine overheating, and “K” may indicate the presence of a defrost button. Using an unsuitable analogue will lead to incorrect operation of the refrigerator.
The length of the capillary tube is another critical parameter. Standard sizes range from 0.5 to 3 meters. If you install a thermostat with a shorter tube, it simply will not reach the mounting location, and a tube that is too long will have to be carefully laid so as not to damage it. In some cases, it is possible to use universal models with a trimmed tube, but this requires high qualifications.
⚠️ Attention: Do not try to shorten the thermostat capillary tube yourself if you do not have the skills to work with refrigeration equipment. Violation of the tightness of the sensitive element system will make the part inoperable.
Below is a table of correspondence of popular models of thermostats installed in refrigerators Biryusa:
| Original / Marking | Popular analogs | Tube length (m) | Features |
|---|---|---|---|
| TAM-133 (K-59) | Ranco K-59, Danfoss 077B6 | 2.5 | Standard for two-chamber |
| TAM-112 (K-50) | Ranco K-50, Danfoss 077B6029 | 0.75 | For single-chamber models |
| TAM-125 | Ranco K-57 | 2.5 | With defrost button |
| TAM-145 | Analogue K-52 | 1.3 | For freezers |
When purchasing a new part, be sure to check the mounting dimensions and location of the mounting holes. Sometimes manufacturers make changes to the housing design, and the new thermostat may not fit into its original position without modifications. It is best to dismantle the old part and take it with you to the store for a visual comparison.
Necessary tools and preparation
To successfully replace the thermostat, you will need a minimum set of tools, which can be found in the garage of most home craftsmen. The main requirement for the tools is serviceability and safety of use. Before starting work, make sure that you have everything you need on hand so as not to interrupt the process while looking for a screwdriver.
The basic set includes Phillips and flathead screwdrivers, side cutters for cutting plastic clamps and pliers. It is also highly advisable to have a multimeter (tester) to check the continuity of the circuit. Without it, the diagnosis will be inaccurate. If the capillary tube of the new part is longer than the old one, you will need a careful tool to install it without creases.
Preparation of the workplace also plays an important role. Free up space in front of the refrigerator, provide good lighting to the inside of the chamber. Defrost the unit in advance and wipe all surfaces dry. Working with wet elements or in close quarters increases the risk of errors and injuries.
☑️ Preparing to replace the thermostat
Don't forget to prepare a container for collecting the water that will remain after defrosting, and a rag for wiping. Cleanliness in the work area is the guarantee that you will not lose small screws and will be able to clearly see the markings of the wires.
Removing the old thermostat
The dismantling process begins with removing the plastic decorative panel covering the thermostat. In refrigerators Biryusa it is usually located inside the refrigerator compartment on the top wall or side. Carefully pry the panel open with a flathead screwdriver or knife, being careful not to break the plastic clips. Under it you will see the regulator handle and rod.
Remove the handle by simply pulling it towards you. Then remove the screws securing the thermostat housing. Their number varies from one to three depending on the model. After removing the fasteners, the control unit will be accessible for removal. Be careful not to pull sharply so as not to damage the wiring.
Next you need to disconnect the wires. Before doing this, it is strongly recommended to photograph the connection diagram or sketch it, since the color marking of the wires may differ from the standard. Use side cutters to cut off the old connector (if it is factory-soldered) or unscrew the terminals. Remove the ground wire, if present.
The most delicate stage is removing the capillary tube from the evaporator. It can be pressed with a metal bar or inserted into a special socket. Carefully bend the fastening bar and pull out the tube. If it becomes sticky or stuck, do not use excessive force to avoid puncturing the thin-walled evaporator.
⚠️ Attention: The capillary tube is very thin and fragile. Use extreme caution when bending or pulling it. Damage to the tube of a new or old thermostat will lead to failure of the sensitive element.
After removing the tube, completely remove the old thermostat. Inspect the installation location for corrosion or damage to the wire insulation. If oxides are found, clean the contacts. Dispose of the old part in accordance with the rules for recycling electrical equipment.
Installation of a new thermostat and connection
Installation of a new one thermostat is carried out in the reverse order of dismantling. First of all, carefully insert the capillary tube into the hole until it stops. It should fit freely into the seat on the evaporator. Secure the tube with a standard strap or fastener, ensuring tight contact with the surface of the evaporator for correct temperature reading.
Fix the thermostat housing in its original place with screws. Make sure it fits snugly and doesn't wobble. The vibration of a running compressor should not be transmitted to the sensitive element, so reliable fixation is mandatory. Make sure that the tube does not touch sharp metal edges, which can cut it over time.
Now let's move on to the electrical part. Connect the new thermostat wires to the refrigerator wiring. If the new device does not have ready-made connectors, use terminal blocks or high-quality insulation (heat shrink). The colors of the wires should match your diagram made during dismantling. Usually this is a phase wire, a compressor control wire and grounding.
After connecting all the wires, carefully lay them inside the case so that they do not get into moving parts (if there is a fan) and do not touch heating elements. Assemble the decorative panel and install the control knob in place. The handle should rotate with moderate force, without jamming.
Checking operation and setting the temperature
After assembly, turn on the refrigerator. In the first minutes of operation, listen carefully: you should hear the characteristic click of the compressor starting. If the engine starts working, this is a good sign. However, don't rush to load the products. Let the refrigerator run idle for several hours to reach normal operation.
To accurately adjust the temperature, it is recommended to use an external thermometer placed in a glass of water in the center of the refrigerator compartment. Set the control knob to the middle position and wait for the temperature to stabilize. The normal range for storing food is considered to be +2...+5°C.
If the temperature does not meet the desired temperature, make adjustments using the adjusting screw, which is often located inside the rod under the handle (accessible through a small hole). Turning clockwise usually increases the temperature (loosens the spring tension), counterclockwise - decreases it.
Pay attention to the cyclical operation. The compressor must be switched off periodically. If it runs continuously for more than 2-3 hours, the new thermostat may be out of range or incorrectly set. In this case, repeated diagnostics are required.
Common mistakes during self-repair
One of the most common mistakes is ignoring the length of the capillary tube. An attempt to stuff the extra length into a small volume leads to creases, which disrupts the circulation of gas inside the sensitive element. This makes the thermostat blind to temperature changes. The tube should lie freely, without tension or sharp bends.
Another mistake is poor contact of the tube with the evaporator. If it is not pressed tightly against the surface, the thermostat will read the temperature of the air rather than the actual cooling surface, which will lead to large temperature differences and infrequent starts of the compressor. The fastening must be reliable.
Grounding is also often forgotten. In older models Biryusa the thermostat housing can serve as part of the ground circuit. If you install a plastic analogue or forget to connect the ground, static electricity or a dangerous potential may appear on the refrigerator body, especially in damp rooms.
Is it possible to install a thermostat from another brand of refrigerator?
Yes, you can, but only if the temperature range and length match capillary tube and mounting dimensions. Most often, analogues from Danfoss or Ranco are suitable. It is important that the temperature range (for example, -24...+10°C) meets the requirements of your chamber.
Why does the refrigerator not turn off after replacing the thermostat?
Possible reasons: the thermostat is incorrectly selected (the shutdown threshold is too low), the adjusting screw is incorrectly adjusted, the capillary tube is not tightly pressed to the evaporator, or there is a freon leak (which is not related to the thermostat).
How to understand that the thermostat is “stuck”?
If, when you tap on the body of a working refrigerator (in the area of the thermostat), the compressor turns off or on, it means that the contacts inside the thermostat are stuck or burnt. This is a temporary solution, the part requires urgent replacement.
Is it necessary to recharge the freon after replacing the thermostat?
No, it is not necessary. A thermostat is an electrical device that is not part of a sealed refrigerant (freon) circuit. Replacing it does not require breaking the tightness of the cooling system, so gas refueling is not performed.