When your reliable refrigerator Biryusa suddenly stops freezing or starts making strange sounds, it’s too early to panic. Often the problem lies in the electrical circuit, which you can diagnose yourself with a simple multimeter on hand. Correct diagnostics allows you to avoid an expensive call to a technician for basic checks and helps you understand whether it is worth repairing the unit or whether it is easier to replace the unit.
Before taking active steps, it is necessary to completely de-energize the equipment. Safety is the main priority when working with electrical appliances. Unplug the plug from the socket and provide access to the back wall of the refrigerator, where the main components that require checking are located.
In this article we will analyze in detail the process of “dialing” key elements: the compressor, the start relay and the defrost system. You will find out which resistance values are considered normal and which indicate a critical breakdown or break, which will allow you to make an informed decision on further repairs.
Preparation of tools and safety measures
For high-quality diagnostics, you will need a digital multimeter (tester). This is a universal device capable of measuring resistance, voltage and current. Make sure that its battery is charged and that the probes do not have insulation damage, since even the slightest defect can distort the readings or lead to an electric shock.
In addition to the tester, prepare screwdrivers (Phillips and flathead) for removing protective covers and panels. On some models Biryusa access to the compressor may be difficult and you will need to remove the rear cover or bottom panel. It will also be a good idea to have electrical tape and a marker on hand for marking the wires if you plan to disconnect the contacts.
⚠️ Attention: It is strictly forbidden to measure the resistance or integrity of a live circuit. All manipulations with the multimeter in the “Ohmmeter” or “Dial” mode are performed only with the device completely disconnected from the network!
The workplace should be well lit. If you are checking the refrigerator in a garage or cottage where it is dark, use an additional light source. Wet hands or a wet floor are also unacceptable - this increases the risk of electrical injury if you accidentally touch bare contacts if there is a residual charge in the capacitors.
Diagnostics of an electric compressor
The heart of the refrigerator is compressor. It is this that creates the pressure for the circulation of the refrigerant. If the motor hums but does not start, or is completely silent, the first thing you need to do is check its windings. There are three contacts on the motor body: common (C), starting (S) and working (R).
Remove the plastic casing from the starting relay and thermal relay. Disconnect the wires from the compressor contacts. Switch the multimeter to resistance measurement mode (limit 2 kOhm or 20 kOhm). Measure the resistance between each pair of contacts. Normal indicators for different models Biryusa may differ, but the general logic is the same.
Between the common contact and the working one, as well as between the common and the starting one, there must be a certain resistance (usually from 10 to 30 Ohms). The resistance between the start and run contacts should be the sum of the previous two measurements. If the device shows one (infinity), it means it is in the winding break. If it shows zero, there has been a short circuit.
Pay special attention to checking for breakdown on the housing. This is a critical stage. Switch the tester to dial mode (with sound) or to the maximum resistance limit (2 MOhm). With one probe, touch any contact of the compressor, and with the other, touch a cleaned place on the metal body of the motor (where there is no paint or rust).
If the device beeps or shows a resistance of less than 1 MOhm, it means that the insulation of the windings is broken and the current flows to the housing. Operate such a refrigerator strictly prohibitedas it is deadly. The compressor must only be replaced.
Checking the starting and thermal relay
The relay is responsible for starting the engine and protecting it from overheating. In refrigerators Biryusa posistor starting relays are often found. Checking them is simple: visually inspect the body for cracks or traces of burning. Then “shake” the relay near your ear. If something inside dangles and rattles, the posistor is destroyed and needs replacement.
The thermal relay (protective tablet) is checked for circuit integrity. When cold, the contacts must be closed. Ring the relay contacts: if you hear a squeak or the resistance is close to zero, the circuit is intact. If there is silence or one on the screen, the relay has burned out and is not passing current to the compressor.
- 🔍 Visual inspection: we are looking for plastic melting, soot on the contacts and swelling.
- 🔊 Sound test: a dangling posistor inside the starting device is a sign of breakdown.
- ⚡ Continuity test: checking the integrity of the thermal relay circuit in a cold state.
Sometimes the problem lies not in the relay itself, but in the oxidation of the contacts. Clean the contact pads with fine sandpaper or alcohol. However, if the plastic has turned black, it is better not to risk it and install a new set of relays, since overheating could change the properties of the metal.
☑️ Relay diagnostics
Testing the defrost heating element and sensors (for No Frost)
If your Biryusa equipped with a system No Frost, a common cause of failure is a malfunction of the defrost system. Ice builds up on the evaporator, blocks the channels, and cold stops flowing into the chamber. The key element here is the heating element (tubular electric heater).
To check the heating element you need to get to the evaporator (usually behind the back wall of the freezer). Disconnect the wires from the heater. We set the multimeter to the limit of 2 kOhm. The resistance of a working heating element is usually from 200 to 400 Ohms (depending on the power, often 400-600 W). If the device shows a break, the heating element has burned out.
Also check the defrost sensor (defroster). It is located next to the heating element or on the evaporator. At room temperature, its resistance should be within a few kiloohms (specific values depend on the model, often around 5-15 kOhms). If the sensor “rings” short or shows a break, it incorrectly transmits the signal to the control module.
| Element | Normal resistance | Fault symptom | Consequence |
|---|---|---|---|
| Defrost heating element | 200 - 400 Ohm | Infinity (∞) | Ice build-up, no cold |
| Defrost sensor | 5 - 15 kOhm (at +20°C) | 0 Ohm or ∞ | The defrost does not turn on or heats constantly |
| Heating element of the refrigeration chamber | 1 – 2 kOhm | ∞ | Water in the pan, ice at the bottom |
| Fuse | 0 Ohm | ∞ | The entire defrost circuit does not work |
Don't forget to check the fuse of the defrost system. It often comes in conjunction with a heating element. If it burns out, the circuit is broken, and the voltage simply does not reach the heater, even if the heating element itself is working.
Why does the heating element burn out?
A frequent reason for the failure of the heating element is poor-quality water, which leaves scale when evaporating, or mechanical damage when defrosting with a knife. Also, the heating element may burn out due to the defrost relay sticking when heating takes too long.
Checking the wiring and limit switches
The electrical circuit of a refrigerator is not only a motor and heaters. An important role is played by the wires connecting the nodes and the door limit switches. Over time, the insulation on the wires can dry out from the heat of the compressor and crack, leading to short circuits.
Carefully inspect the wiring harnesses leading from the control unit to the compressor and sensors. Look for signs of melting, chewing or abrasion. Pay special attention to the places where the wires enter the refrigerator body - they often get bent there.
The door end (button or magnetic sensor) controls the light and, in some models, the fan. If the limit switch is stuck or oxidized, the refrigerator may “think” the door is open and not turn on the cooling or fan. Ring the limit switch: when pressed, the resistance should drop to zero (or vice versa, depending on the type - normally closed or open).
⚠️ Attention: In modern models Biryusa with electronic control, the sensor wiring is very thin. When making calls, do not pull the wires so as not to tear them off the board. Use careful movements and, if necessary, secure the bundles with zip ties.
If you find a broken wire, it can be restored, but the connection must be carefully insulated with heat shrink or high-quality electrical tape that is resistant to low temperatures. Ordinary electrical tape can come off in the cold.
Analysis of the control board and module
If all mechanical and electrical components (compressor, relays, heating elements, wiring) are working, and the refrigerator does not work, the problem may lie in control module. The electronic board sends commands to turn on the nodes. Checking the board requires knowledge in electronics, but basic diagnostics can be done.
Inspect the board visually. Swollen capacitors, blackened traces, traces of insects or moisture are clear signs of a malfunction. If traces of corrosion are visible on the board, water may have entered the refrigerator during defrosting or washing.
Check the fuse on the board itself. Often it is this that burns out, protecting the circuit from power surges. If the fuse is intact, but the board does not respond (no indication, no relay clicks), professional diagnostics with an oscilloscope or replacement of the module is required.
Frequent diagnostic errors
Beginners often make mistakes that lead to false conclusions. For example, trying to measure the resistance of a running engine. As already mentioned, this cannot be done. It is also often forgotten that some sensors have a nonlinear characteristic, and their resistance varies with temperature.
Another mistake is ignoring the state of the contacts. Even if the part is in good condition, the oxidized connector will create a high contact resistance and the unit will not work. Always clean the contacts before installing a new part.
- ❌ Measuring under voltage: An attempt to ring the circuit without unplugging the device from the outlet will burn the multimeter.
- ❌ Dirty probes: oxidized ends of the tester probes give incorrect resistance readings.
- ❌ Ignoring temperature: checking temperature sensors without taking into account their current temperature (cold or hot).
Be attentive to details. If you replaced the compressor, but did not flush the system of combustion products from the old motor (if there was a breakdown), the new compressor will also quickly fail. Diagnostics must be comprehensive.
Is it possible to ring the compressor without removing the relay?
Theoretically, you can try to find the contacts through the connectors, but this is extremely inconvenient and often gives false results due to parallel circuits inside the relay. For accurate diagnostics, it is better to remove the relay and wire from the compressor.
What resistance is considered normal for windings?
For domestic refrigerators Biryusa the resistance of the starting winding is usually 30-40 Ohms, and the working winding is 10-15 Ohms. The total resistance between the starting and operating contacts must be equal to the sum of these values. What is more important is the absence of breakdown on the case.
What to do if the multimeter shows 0 Ohm?
A reading of 0 Ohm (or close to it) between the contacts where there should be resistance, or between the contact and the case indicates a short circuit. Such a unit (compressor, heating element) cannot be repaired and requires replacement.
Is it necessary to discharge the capacitors before checking?
Yes, there may be residual charge in the control units and starting devices. Before touching the contacts with the probes, it is recommended to short-circuit the terminals of the capacitors with a screwdriver (with an insulated handle) or simply wait a few minutes after disconnecting.
Why does the Biryusa refrigerator click but does not start?
The click is the operation of a thermal relay or an attempt to turn on the starting relay. If this is not followed by a humming sound from the engine, it means the compressor is not starting. Reasons: jammed compressor, burnt out start relay, broken winding or low voltage in the network.