Unexpected failure of the temperature control system c Biryusa 18 often becomes an unpleasant surprise for the owner. If the compressor stops turning on or, on the contrary, works without stopping, ignoring the set parameters, then with a high degree of probability the culprit is thermostat. This device is responsible for opening and closing the electrical circuit depending on the temperature inside the chambers.
Independent replacement of this element allows you to save a significant amount on calling a technician, since the design of the 18-series model is quite simple and repairable. However, before starting work, you need to make sure the diagnosis is correct and prepare the instrument. Incorrect diagnosis can lead to the purchase of unnecessary spare parts, so it is important to check all the symptoms.
In this article we will analyze a detailed algorithm of actions, from dismantling the old regulator to the final check of the unit’s performance. You will learn how to choose the right analogue if the original is not on sale, and what installation nuances exist for different modifications Biryusa 18. Remember that working with electrical appliances requires strict adherence to safety precautions.
Diagnostics of a thermostat malfunction
Before disassembling the refrigerator, you need to localize the problem. The main sign of a breakdown is a violation of the temperature regime. If the food in the main chamber begins to deteriorate or, conversely, freezes at the back wall, and the regulator knob does not respond to turns, this is the first alarm. It is also worth paying attention to the operating cycle of the motor.
Often users confuse a breakdown of the thermostat with a freon leak or a compressor malfunction. The key difference is the behavior of the motor-compressor. If there is a defect thermal sensor the unit is either silent or hums non-stop, without pausing to rest. In the event of a refrigerant leak, the compressor may work for a long time, but the refrigerator will barely cool.
⚠️ Attention: Before any diagnostics, be sure to disconnect the refrigerator from the power supply. Checking contacts with a multimeter is only possible with a de-energized device to avoid short circuits.
For an accurate check, you can use the exclusion method. If possible, temporarily install a known-good thermostat. If the refrigerator works normally, it means that the old element has really failed. Also visually inspect the contacts: oxidation or melting indicates overload or a poor connection.
Necessary tools and preparation
Successful repairs do not require complex professional equipment. A standard DIY kit is sufficient. The main thing is to have a working measuring device on hand to test the circuits. Without a multimeter or continuity tester, it will be more difficult to work, since you will have to act at random.
It is important to prepare the workplace in advance. The refrigerator Biryusa 18 has dimensions that require space to access the top of the case. Move the unit away from the wall, allowing rear and side access. Defrost the chambers in advance if there is ice left in them, so that water does not get on the electrical components.
☑️ Preparation for repair
The list of necessary tools includes:
- 🔧 Screwdrivers (phillips and flat) for removing panels.
- 🔌 Multimeter for checking the integrity of contacts.
- ✂️ Pliers for ease of working with wires.
- 🧤 Dielectric gloves for safety.
- 📸 Smartphone for photographing the connection diagram.
Removing the old thermostat
The process of removing a faulty part in the model Biryusa 18 begins with access to the installation site. In most modifications, the thermostat is located inside the refrigerator compartment in a plastic box or directly on the external control panel if the model is modern. In classic versions, you need to remove the top cover or the lampshade.
Carefully unscrew the mounting screws holding the protective panel. Do not use excessive force, as the plastic in older refrigerators can be brittle. After removing the cover, you will see the thermostat itself with a capillary tube extending from it, which goes into the evaporator.
The next step is to disconnect the electrical wires. The critical thing here is to take a photo of the wiring diagram before you disconnect even one wire. The colors of the insulation may fade over the years of use, and you cannot rely solely on them. Mark each wire with a marker according to their location on the terminals.
⚠️ Attention: The capillary tube of the thermostat is very thin and sensitive to creases. When removing the sensor from the evaporator, act as carefully as possible, do not pull sharply.
After disconnecting the wires, you must remove the sensitive element from the socket in the evaporator. Usually it is simply inserted into the technological hole. Pull the thermostat housing smoothly to release the tube. If it is stuck, you can slightly rock it from side to side, but without jerking.
Connection diagram and installation of a new element
Installation of a new one thermostat is done in the reverse order of dismantling. First, carefully insert the capillary tube into the evaporator hole at the same depth as the previous element. Insufficient immersion of the sensor will lead to incorrect temperature readings.
Then comes the most crucial moment - switching the wires. Use the photo you took earlier or the diagram below for proper connection. An error in the connection can lead to the burning of a new thermostat or even a compressor immediately after switching on.
| Contact on the thermostat | Wire color (typical) | Function |
|---|---|---|
| Input (L) | Red / Brown | Power supply |
| Output to compressor | Black / Green | Start motor |
| Grounding | Yellow-green | Case protection |
| Lamp (optional) | White / Orange | Camera lighting |
After connecting the wires secure the thermostat housing in its original location. Ensure that the adjustment screw or knob is accessible to the user and not blocked by structural elements. Check that all connections are firmly secured by lightly tugging.
What to do if the wires are not the right length?
If the standard wires of the new thermostat are shorter, they can be extended using copper wire of the same cross-section. Be sure to make the connection through a terminal block or high-quality twisting followed by heat shrink insulation. Do not leave the twists open inside the chamber.
Setting up and checking operation
After assembling the refrigerator, do not rush to load food. Do a test run first. Turn on the unit and set the control knob to the middle position. The compressor should start almost immediately or after a few seconds if the protection is on.
Let the refrigerator operate until the first automatic shutdown. This can take from 30 minutes to an hour, depending on the ambient temperature and the condition of the seals. At this moment, listen for a click - the thermostat has broken the circuit. If the motor stops, it means the system is working correctly.
Check the adjustment range. Turn the knob to the minimum cold position and wait until the motor stops (if it was running). Then turn it up to maximum - the compressor should turn on again. If the cyclicity is observed, the repair can be considered successful.
Common mistakes when replacing
Beginners often make mistakes that nullify all efforts. One of the most common is incorrect installation of the capillary tube. If it does not fit tightly to the evaporator or is not inserted completely, the thermostat will “lie”, considering the temperature in the chamber higher or lower than the real one.
Another mistake is ignoring grounding. Some craftsmen simply insulate the ground wire, considering it unnecessary. This is a serious security breach. In the event of a breakdown of the insulation on the body, the refrigerator will become deadly if touched.
It is also worth mentioning the selection of analogues. Not all thermostats are interchangeable. Differences may be in the length of the capillary tube, temperature range and contact position. Installing an unsuitable model will lead to incorrect operation or rapid failure.
⚠️ Attention: If after replacement the refrigerator begins to work incorrectly (for example, it freezes too much), do not rush to blame the new part. Check the tightness of the doors and the condition of the sealing rubber.
Choosing a suitable spare part
When purchasing a new thermostat for Biryusa 18 pay attention to the markings. Original spare parts have certain codes, but there are also high-quality analogues from well-known brands, such as Tam, K59 or Ranco. The main thing is the coincidence of the temperature range.
It is important to consider the length of the capillary tube. It can vary from 0.5 to 3 meters. The excess length can be carefully rolled into a ring and secured, but you cannot extend the tube yourself - this will break the tightness of the sensitive element system.
When choosing, pay attention to the number of contacts. For refrigerators with a single compressor, three contacts are usually sufficient, but there are models with additional functions that require four or five contacts. Visually compare the new element with the old one before purchasing.
Is it possible to use a thermostat from another refrigerator?
The use of analogues is possible if the main parameters are the same: temperature range actuation, capillary tube length and contact arrangement. However, it is better to look for specialized analogues specifically for the Biryusa 18 model in order to avoid problems with setup.
Why does the refrigerator not turn off after replacement?
There may be several reasons: the thermostat is incorrectly selected (too wide range), the capillary tube is installed incorrectly (does not reach the cooling zone) or the new regulator itself is faulty. It is also worth checking the tightness of the chambers.
How can you tell that it is the thermostat that has burned out and not the relay?
If you hear a click from the relay when you turn it on, but the compressor does not start and hums, the problem is in the starting relay or motor. If there is not even a click or reaction, and continuity shows an open circuit on the thermostat at room temperature, the thermostat is to blame.
Is it necessary to change the thermostat if the refrigerator just starts to freeze worse?
Not necessarily. First check the door seals, defrost the unit completely and clean the condenser at the back. Deterioration in cooling is often associated with a freon leak or contamination of the system, rather than with electronics.