Refrigerators of the series Biryusa 22 are deservedly considered "workhorses" of domestic production, characterized by reliability and simplicity of design. However, even the most time-tested units eventually have failures in the electronics or mechanics of the temperature control system. If you notice that the refrigerator has stopped turning off, is running continuously, or, conversely, has stopped cooling, and an ice coat has formed inside the chamber, most likely the problem lies in the thermostat.
Replacing this element is one of the most common procedures in repairing household appliances, which you can do yourself with a minimum set of tools. The dismantling process thermostat in Biryusa 22 models has its own design features related to the location of the evaporator and the method of fastening the regulator. In this article we will analyze in detail all stages of work, from preparation to final inspection.
Before taking active steps, you need to make sure that the diagnosis is correct. Symptoms of a thermostat malfunction are often confused with a freon leak or compressor failure. If the engine hums, but there is no cold, or if it does not start at all, even when you turn the adjustment knob all the way, this is a sure sign that the control circuit is broken or shorted inside the sensor.
Diagnostics of a thermostat malfunction
The first stage of any repair should be an accurate diagnosis. In refrigerators Biryusa 22 the thermostat is responsible for opening and closing the electrical circuit of the compressor depending on the temperature in the chamber. If the contacts inside the device are “stuck” in a closed state, the compressor will work non-stop, trying to cool the chamber to impossible temperatures. In this case, a thick layer of ice forms on the back wall, and the food in the chamber may freeze.
There is a simple method of initial check that does not require disassembling the unit. Try turning the thermostat knob counterclockwise until it stops (to the “minimum” or “off” position). If the compressor continues to operate and the characteristic hum does not stop, this indicates a malfunction of the thermostat. In good condition, when the handle is turned to the far left position, the circuit should open and the engine should stop.
However, visual signs and behavior of the motor are only indirect evidence. To be 100% sure, you need to test the contacts with a multimeter. If the device shows a “break” in any position of the handle or, conversely, a “short circuit” constantly, the element must be replaced. It is also important to check the integrity of the capillary tube that extends from the thermostat body.
⚠️ Attention: If the capillary tube of the thermostat has traces of creases, kinks or mechanical damage, such a sensor cannot be used. Violation of the capillary tightness leads to refrigerant leakage from the bellows, and the thermostat stops responding to temperature changes.
For accurate diagnostics, you will need a multimeter set to resistance measurement mode (Ohms). Before starting measurements, be sure to turn off the power to the refrigerator by removing the plug from the socket. Remove the adjustment knob and plastic cover to gain access to the terminals. Disconnect the wires from the thermostat and connect the multimeter probes to the corresponding contacts.
Necessary tools and preparation
The success of the repair directly depends on the correct preparation of the workplace and the availability of the right tool. Refrigerator repair Biryusa 22 does not require complex specialized equipment, but the basic kit of a home craftsman must be fully equipped. The absence of the required screwdriver can lead to damage to the plastic elements or breakage of the fastener threads.
First of all, you will need a Phillips screwdriver, preferably with a magnetic tip, so as not to drop the screws into hard-to-reach places in the case. You may also need a small flathead screwdriver to pry up plastic latches or remove decorative caps. It would be a good idea to prepare pliers to carefully remove the wires.
Indispensable for checking the electrical part multimeter. Without it, replacing the thermostat turns into guessing on coffee grounds. Also prepare a container for defrosting, if there is ice in the chamber, and a dry rag. Working with electrical wiring in conditions of high humidity is dangerous, so the inside of the chamber must be dry.
☑️ Preparation for repair
The procedure for dismantling the thermostat
The process of removing the thermostat in models Biryusa 22 requires consistency to avoid damaging fragile controls. Unlike modern models, here the mechanics are often integrated directly into the control panel or mounted on the inner wall of the chamber. You should start by dismantling the temperature control knob.
The handle is usually simply pulled onto the thermostat rod and held in place by friction. To remove it without damaging the plastic, you need to gently pull it towards you, slightly rocking it from side to side. If the handle fits very tightly, you can use a thin fabric to prevent your fingers from slipping, but it is not recommended to use metal objects for prying.
After removing the handle, you will see a decorative panel or the thermostat housing itself. In some modifications Biryusa 22 it is necessary to unscrew the screws securing the control panel to the refrigerator body. Be careful: the screws may be hidden under plastic plugs or stickers.
When the fasteners are removed, carefully move the panel to the side. Under it you will see the thermostat itself - a metal cylinder with a long thin tube (capillary) coming out of it. The capillary tube is inserted into the evaporator through a special hole and can be secured with a bracket or simply inserted into a groove.
Feature of fastening the capillary
In some versions of Biryusa 22, the capillary tube fits tightly into the hole of the evaporator and is fixed with sealant. When replacing the thermostat, the old sealant must be carefully removed, and the new sensor must also be placed on a thermally conductive sealant for correct operation.
The next step is to disconnect the electrical wires. Before removing them, it is strongly recommended to photograph the connection diagram or sketch it. Wire colors may vary between batches and assembly errors may result in a short circuit. The wires are usually fixed to the thermostat terminals.
⚠️ Attention: Never pull the wires with force. In old refrigerators, the insulation becomes fragile, and the wire may break at the terminal itself, which will require additional soldering and restoration of the circuit.
After disconnecting the wires, it is necessary to free the capillary tube. It passes through the wall of the refrigerator into the evaporator. Carefully pull the thermostat out of its seat, being careful not to bend the tube at an acute angle. Then remove the sensor element from the evaporator. If it has become stuck, do not use force - it is better to slightly warm the entry point with a hairdryer (be careful not to melt the plastic).
Connection diagram and marking of wires
Correct connection of the new thermostat is the key to safe operation of the refrigerator. The model Biryusa 22 usually uses a thermostat with three contacts, although only two or three can work, depending on the modification. There are markings on the body of the device that will help you navigate.
Contacts are indicated by numbers or letters. The most common designations are 1-2-3 or 3-4-6. The contact to which the mains wire (phase) is connected is usually connected to one of the outer terminals, and the wire from the compressor is connected to the other. The third contact can be used to connect a compressor operation indicator lamp or be isolated.
| Contact marking | Function | Wire color (typical) | Where to connect |
|---|---|---|---|
| 3 (or L) | Network input (Phase) | Brown / Red | From plug/mains |
| 4 (or 1) | Output to compressor | Black / Green | To start relay |
| 6 (or 2) | Indication / Ground | Yellow / White | To the lamp or insulate |
If you install a universal analogue instead of the original thermostat Biryusa, the colors of the wires may not match. In this case, focus solely on the logic of operation: one wire is the incoming phase, the other is the outgoing phase to the motor. The third wire, if it led to the “Network” or “Operation” light, is connected to the corresponding contact on the new thermostat, if such a function is provided.
For reliable contacts, it is recommended to use terminal blocks or properly insulate the twists with heat-shrinkable tubing. Simple electrical tape in a refrigerator can come off over time due to condensation and low temperature, which will lead to oxidation of the contacts.
Installing a new thermostat
Installing a new one thermal sensor is done in the reverse order of dismantling. First of all, it is necessary to correctly place the sensitive capillary tube in the evaporator. Immersion depth and location are critical for correct operation. If in the old model the tube was pressed with a metal plate or bracket, the new one must also be fixed in the same way.
Make sure that the tube does not touch the heating elements (if any) and does not have sharp bends. The bending radius should be smooth, at least 5 times the diameter of the tube itself. After installing the tube, the thermostat housing is installed in its normal place and fixed with mounting screws.
Next, the electrical wires are connected according to the diagram or photograph made earlier. Make sure the wires are not under tension or touching moving parts or sharp metal edges. The wiring harness is neatly placed in the channel or niche intended for it.
The last stage of assembly is the installation of the decorative panel and temperature control knob. The handle is put on the rod until there is a characteristic click or stop. Make sure that it rotates freely and does not touch the body.
⚠️ Attention: Technical characteristics of thermostats may vary depending on the year of manufacture of the refrigerator. Always check the markings of the new sensor with the data specified in the technical documentation for your Biryusa 22 model, or consult with the seller of spare parts.
Checking functionality and setting
After assembly, the moment of truth comes - checking the operation of the refrigerator. Turn on the unit and set the thermostat knob to the middle position. The compressor should start immediately (if the chamber temperature is higher than the set temperature). After some time, when the temperature inside reaches the set value, the engine should turn off.
Pay attention to the operating cycle. For refrigerators Biryusa 22 the normal mode is one in which the compressor runs for about 10-15 minutes and rests for 20-30 minutes (depending on the load and room temperature). If the refrigerator turns off too quickly (after 1-2 minutes) or does not turn off at all, adjustment is required.
On the body of some thermostats there is an adjustment screw hidden under a seal or plastic plug. Rotating this screw changes the contact opening temperature. However, if you have installed a new, working thermostat, the factory setting, as a rule, does not require intervention.
What to do if the refrigerator “threats” without stopping?
This may mean that the thermostat does not sense the cold, or its capillary is in poor contact with the evaporator. Check the tightness of the tube. Also, the cause may be a freon leak - in this case, replacing the thermostat will not help.
During the first day after replacement, it is recommended to periodically check the temperature in the chamber using an external thermometer. This will ensure that the food does not freeze or spoil. If all parameters are normal, the repair can be considered successfully completed.
Is it possible to install a thermostat from another refrigerator model?
Yes, you can often use universal analogs or sensors from other models (for example, TAM-133, K-59), if they are suitable in size, capillary tube length and temperature range. The main thing is the coincidence of the electrical parameters and the type of contacts.
Why does the new thermostat click, but the compressor does not start?
The click means that the contacts open/close, but no current flows. Possible causes: a faulty compressor start relay, a faulty motor winding, or a problem with the wiring between the thermostat and the motor. You need to ring the circuit further.
How to determine what length of capillary tube is needed?
The length of the tube should be sufficient to bring the sensitive element to the end of the evaporator (usually 0.5 - 1.5 meters). The excess tube is carefully rolled into a ring and placed inside the housing, avoiding kinks. A tube that is too short will not give correct readings.
Is it necessary to defrost the refrigerator before replacing?
Yes, complete defrosting is required. Working with electrical wiring and metal parts inside a wet chamber is dangerous. In addition, ice can interfere with access to fasteners and the capillary tube.
What to do if the adjustment knob is broken?
The handle can be temporarily replaced with a plug or piece of plastic that is suitable in diameter, but it is better to order an original spare part. Operation without a handle is inconvenient, since it is difficult to accurately set the temperature.