A sudden failure of refrigeration equipment always becomes an unpleasant surprise, especially if perishable products are stored in the chamber. For owners of domestic brand equipment Biryusa one of the most common causes of failure is a breakdown of the thermostat, which in everyday life is often mistakenly called a thermostat. It is this unit that is responsible for turning the compressor on and off, maintaining the set temperature. If you notice that the unit has stopped freezing or, conversely, works non-stop, turning food into an ice ball, most likely the problem lies in the temperature sensor.
Independent replacement of this element is quite within the capabilities of a home craftsman who has a minimal set of tools and basic skills in handling electrics. However, before starting work, it is important to understand that thermal relay this is a complex mechanical device that requires careful handling. In this article, we will analyze in detail the diagnostic and replacement process so that you can return your refrigerator to functionality without calling a technician.
Diagnostics of a thermostat malfunction
Before disassembling the unit and buying a new part, you need to make sure that the problem is in the temperature controller. Symptoms may be similar to a compressor or start relay failure, so accurate diagnosis is critical. The main sign of a malfunction thermostat is a violation of the cyclic operation of the motor. The refrigerator can either be silent or hum continuously, without turning off even when ice has already formed inside the chamber.
For an initial check, you can use the simple “defrost” method. Unplug the device, defrost it completely within 24 hours and leave it with the doors open. After this, turn on the unit. If the compressor started working, but after a short time stopped again without cooling the chamber to the required values, this is a sure sign that thermal sensor does not detect a decrease in temperature.
⚠️ Attention: If, when turned on, the refrigerator makes a click and buzzes for a couple of seconds, and then clicks again and goes silent, the problem may not be with the thermostat, but with the start relay or the compressor itself. Do not rush to change working parts.
Another way to check is by directly closing the contacts. With the refrigerator unplugged, remove the control knob and protective cover. Remove the thermostat, leaving the wires connected, and short the two main wires (usually pins #3 and #4) with a jumper wire. If, after connecting to the network, the compressor started working and began to freeze, then the circuit is working properly, and the thermostat needs to be replaced.
Preparation for replacement and selection of spare parts
After making sure that replacement is necessary, you should select the right spare part. Thermostats for refrigerators Biryusa may differ in the length of the capillary tube, temperature response range and type of fastening. The most common models are the TAM series, K-59 or domestic analogues. An incorrectly selected part will lead to incorrect operation: the chamber will either be undercooled or the food will freeze.
When choosing, pay attention to the markings of the old device. The numbers and letters on the case are not random: they indicate the temperature thresholds for turning on and off. For example, single-chamber models often use thermostats with a wider range, while dual-chamber models require more accurate sensors. The length of capillary tubeis also important: if it is too short, you will not be able to correctly place the sensitive element in the chamber.
To carry out the work you will need a standard set of tools. Don't forget to prepare a container to catch any water that may remain in the drainage system and a flashlight to illuminate the work area. It is also recommended to have a multimeter on hand for the final check of contacts.
☑️ What to prepare before repair
Removing the old thermostat
The replacement process begins with completely disconnecting the refrigerator from the power supply. This is a mandatory safety condition, since work will be carried out on electrical components. Once unplugged, remove all food and shelves from the refrigerator compartment to allow clear access to the rear wall where the evaporator and thermostat are usually located.
Remove the temperature control knob. Depending on the model Biryusa, it can simply be removed by hand or require prying with a flat-head screwdriver. Under the handle you will see a mounting screw or plastic nut that secures the thermostat housing. Carefully unscrew the fasteners, trying not to damage the plastic case, which can become fragile from the cold.
Now you need to remove the thermostat itself. It is held on by latches or screws inside the niche. Be extremely careful with the capillary tube: it is a thin copper tube filled with freon that is very easy to pinch or burst. Smoothly pull the sensor out of the mounting hole in the evaporator. If the tube is long, carefully roll it into rings, avoiding creases.
What to do if the capillary tube is stuck?
Sometimes the tube sticks to the evaporator or gets stuck in the plastic channel. Do not pull with force under any circumstances! Try gently warming the tube exit area with a hairdryer at minimum temperature or using a thin wire to loosen it. Sudden movements can lead to depressurization of the system.
Installing a new thermostat
Installation of the new part is carried out in the reverse order of dismantling. First of all, install the sensing element (capillary tube) in the same hole where the old sensor was located. The immersion depth must be identical, otherwise the thermostat will read the temperature incorrectly. Secure the tube with a standard fastener or an aluminum plate, if provided by the design.
Next, you need to connect the electrical wires. It is extremely important here not to confuse the contacts. Before disconnecting the wires from the old thermostat, it is highly recommended that you take a photo of the wiring diagram or mark the wires with a marker. Usually the wires are color-coded, but in older technology the colors may fade, so it is better to rely on the diagram or previously made marks.
Insert the thermostat housing into the niche and secure it with screws or latches. Install the temperature control knob. After assembling all mechanical parts, you can proceed to testing. Turn on the refrigerator and set the control knob to the middle position.
| Parameter | Old thermostat | New thermostat | Normal |
|---|---|---|---|
| Switch-on temperature | Unknown | -12°C | Depends on the model |
| Switch-off temperature | Unknown | +4°C | Depends on the model |
| Tube length | 2.5 m | 2.5 m | Same |
| Contact type | Normally closed | Normally closed | Coincident |
Setting up and checking operation
After replacing the thermostat, the refrigerator should work. During the first hours of operation, the unit can operate in enhanced mode, gaining temperature. Your task is to control the first cycle of work. The compressor should turn off when the temperature in the chamber reaches the set values. For single-chamber models Biryusa this usually happens when the temperature reaches about +2...+4 degrees.
If the refrigerator turned off, but the food was not frozen, or, conversely, turned off too early, adjustment may be required. On the body of some thermostats there is a screw under a seal that allows ( - fine-tune) the response range. However, you shouldn’t go there without special equipment and experience, as you can completely throw off the calibration.
⚠️ Attention: If after replacing the thermostat the refrigerator operates jerkily (turns on for 10 seconds, turns off for 5 minutes), you may have chosen the wrong thermostat model or made a mistake when connecting the wires. Immediately disconnect the device from the network.
Check the tightness of the capillary tube. It should not dangle or touch hot parts of the refrigerator. The correct location of the sensitive element guarantees long and stable operation of the entire cooling system.
Frequent errors and troubleshooting
Even when following Newbie instructions often make mistakes. The most common of them is damage to the capillary tube during installation. If you hear a hissing sound or smell the oil, it means that the freon has gone out, and the thermostat, and possibly the entire refrigerator, requires professional repair with refilling.
Another mistake is ignoring cleaning the contacts. If the wires are oxidized, the new thermostat may not work properly. Use fine sandpaper or a file to clean the ends of the wires before connecting. It is also important to securely insulate the twist points if you do not use terminal blocks.
Some users try to repair an old thermostat by disassembling its housing. This is a path to nowhere: there is a sealed bellows chamber inside, and it is impossible to restore its factory settings at home. Repair is not economically feasible and technically impossible without special equipment.
Can a universal thermostat be used?
There are universal models with adjustable tube length, but their installation requires high qualifications. It is better to use the original analogue, specially designed for the Biryusa series of refrigerators.
How often do you need to change the thermostat in the Biryusa refrigerator?
The thermostat does not have a strict expiration date and is changed only after a breakdown. Under normal operating conditions, it lasts 10-15 years or more. Frequent replacements may indicate power surges in the network or problems with the cooling system.
Why does the Biryusa refrigerator not turn off after replacing the thermostat?
There may be several reasons: the thermostat model is incorrectly selected (wrong temperature range), freon leak, compressor malfunction or error when connecting the wires. It is also possible that the door is skewed, causing warm air to enter the chamber.
Where can you find the thermostat marking if it has been erased?
If the marking on the body is not readable, focus on the parameters of your refrigerator: chamber volume, type (single-chamber/double-chamber) and year of manufacture. It is best to remove the old part and choose an analogue in a specialized store, comparing the length of the tube and the location of the contacts.
Is it dangerous to change the thermal relay yourself?
Replacing the thermal relay involves electric current and refrigerants. If you follow safety rules (unplugging) and are careful, the risk is minimal. The main danger is to damage the capillary tube, which will lead to freon leakage.