The most progressive development in the field of cookers can be considered a unit with an induction hob. This technology attracts buyers because it does not require the use of gas, as well as its novelty. But, despite high technology, malfunctions in induction cookers occur no less than other household appliances.
The principle of operation of the induction cooker
The induction heating plate works on a fairly simple principle of generating eddy currents in a magnetically and electrically conductive material. We are talking, first of all, about metals and their alloys with certain physical characteristics. In order for the induction heating element to work properly, the following conditions must be met.
- Use dishes made of special materials. Most often it is steel. It is this material that has not only good ferrimagnetic characteristics, but also the ability to generate eddy currents and actively absorb the energy generated during their passage.
- The heater power control system must provide creation of an alternating magnetic field. It is this that generates eddy currents in the material of the dishes. The field frequency is in the range from 20 to 60 Hz and must be stable.
- The magnetic field of an induction heater is quite strongly localized. This means that the object to be heated must be as close as possibleto achieve maximum process efficiency.
If we consider the induction cooker and the dishes installed on it from the point of view of physical processes, this system is a transformer. In this case, the heater coil acts as the primary winding. The magnetic field generated by it causes the appearance of eddy currents in the dishes. It is the bottom of this object that acts as a secondary winding. There is no removal of electrical energy from it, so all of it is converted into heat. As a result, the pot or pan heats up.
Important! For normal and efficient operation of the induction hob, it is necessary that the coil area be as close as possible to that of the object installed on it. In this case, the energy is transferred almost completely.
If this condition is not met, the following unpleasant things happen:
- eddy currents do not form over an empty, uncovered place on the stove;
- the coil generated by energy on uncovered, empty places is not utilized;
- as a result of incomplete energy removal, the coil overheats.
To neutralize this phenomenon in each induction hob cooling radiators installed. If they fail, the coil will have to be changed. And in the most difficult cases, the output stages of the high-frequency power generation circuit will also require repair.
Modern induction cookers are equipped with an information board and self-diagnostic systems. If some problems are detected, the device itself will inform the user about what happened. Error codes for plates of some manufacturers look like this:
|Overheating of the internal elements of the device
|Wrong supply voltage
|E0, E10, EA, E3
|E7 (E:07), E8 (E:08)
For users with repair skills and a sufficient level of knowledge, the error code will show exactly where to look for the problem. For the rest, this is an indication that you need to seek qualified help.
Stove disassembly and troubleshooting
If simple checks in the form of testing the supply voltage and examining possible places for broken contacts have been passed and have not yielded results, one thing remains. The plate needs to be disassembled for a complete repair. It is recommended to do this only if you have the appropriate knowledge in the field of electrical circuits.
Advice! Disassembly is done carefully and carefully. It is recommended to take a photo after each step to make it easier to assemble the slab.
After removing the top decorative panel, the user will see the coils adjacent to it and their cooling system. At this stage, you need to carefully look around. Soot, discoloration of windings or individual components of the electrical circuit will show in places of possible malfunctions. Traces of melting are also important. It is from the points where such shortcomings are found that further research should begin.
If visually everything is fine, you will have to check everything without exception. Here it will not be superfluous to have a schematic diagram of your stove on hand. It can usually be downloaded from the manufacturer’s website or found on thematic forums.
A typical checklist looks like this.
- Power circuits are being investigated. This is a block of fuses, if they are broken, they are changed. Cables and wires are called to make sure they are intact.
- Coils being inspected. Their spirals should have a uniform winding structure, without damaged conductors, traces of soot on the varnish.
- Temperature sensors are being tested. This is done with a multimeter. When heated, the element changes conductivity. Therefore, a source of local heat, such as a soldering iron, is useful.
- The connections from the coils to the high-frequency generator are being investigated. Cables are called, contact groups are inspected.
- Control board in conditions of limited space inside the plate is heated. It needs to be examined for possible cracks. Tracks must be checked. If they have cracks, including due to corrosion processes after damage to the protective coating, they are eliminated.
- Dismantled non-working burner. It is removed together with the generator module. Pay is being looked at. Parts that have failed are usually immediately visible by changes in the color of the case or contact groups. This is where the schematic diagram of the stove comes in handy. Often on small parts it is simply impossible to read the marking due to the burning of the case. What exactly to put – learn from the circuit diagram.
Insufficient heating power
This hob malfunction can cause wrong pot position on the stove: not in the center of the burner, but on the side, or the fact that the dishes themselves are of a smaller diameter than the hob itself. If everything is in order with the diameter of the cookware, then you should check the fit of the induction burner to the glass-ceramic hob. If it is not in tight contact with the panel, achieve a good fit using special pressing springs.
When the indicator flashes between the set power indicator and the reduced power value, it can be said that the control unit has automatically reduced the power of the hob due to overheating of the induction coil. In such situation check the condition of the coil.
One of the burners is not working
At the very beginning, including the panel, the desired burner is selected using sensors. Only after selecting it, you can set the power level. If the correct sequence has been followed, but the inclusion does not occur, check what the dishes are made of. It must be either metal or cast iron, that is, have property to be magnetized. Aluminum and copper cookware is not suitable for induction cookers. Also, it will not work to cook on such a hob in glassware.
In the case when the dishes meet the required standards, but the problem remains, it is necessary to start the execution test programsto check the hotplate temperature sensor. If it fails, it must be replaced. With a working sensor, the tightness of the induction module to the glass-ceramic panel is checked. If necessary, the fit is adjusted by pressure springs.
The left pair of burners does not work
To find out the reason why the block of hobs located on the left does not turn on, it is required check all connections from the coils to the control unit and to the power board. If you find that there are no connection problems, then you need to replace the control unit. In the absence of positive results, the block of burners must be replaced.
Error codes on the display can signal poor contacts in the wiring between the modules of the unit. In this case, the code “E8” appears.
The right pair of burners does not work
When looking for a malfunction in a Bosch induction hob or a similar hob from another company, you should check the contacts located in the terminal box, as well as the condition of the fuse for the coil unit. At fuse blown, it needs to be replaced with a new one, with the same marking. If there is no change in a positive direction, check as described above for the left pair of cooking places.
Also, the LCD may display error code “E6”. This error means that the induction hob has failed. It is recommended to disconnect the unit from the mains for 30 seconds, and then turn it on again. If the error codes reappear, the control panel will need to be replaced.
The stove does not turn on and there is no indication
First of all, you need to check the fuse, and then the mains switch. The next step is to check the connection between the control unit and the power board. Then between the control unit and the touch panel. If a failed module is found, it must be replaced. If replacing the module does not help, the entire coil unit is replaced.
The confirmation of problems in the touchpad can be error code “E9”that appears on the machine’s LCD. Based on the list of error codes, it means that the touch control panel is faulty. It is recommended to unplug the machine for 30 seconds. When the error reappears, the control panel changes.
Residual heat indicator not working
Need to run software test to test the temperature sensor. If it is working, the control unit changes. There are cases when the elements of the LCD display are constantly lit or not all work. With such a malfunction, the quality of the connections between the control unit and the touch panel is checked. You can try to replace the cable connecting the modules. If this does not help, the control unit must be replaced.
Cooling fan malfunction
The cooling fan can run continuously if you have set the maximum heating power for the burners. Also, it may not turn off if the air temperature around it is more than 50°C. Otherwise, the malfunction may be caused by a failed control unit, which must be replaced.
In this case, the unit may also display error codes on the display. For a failed fan, this will be the error code “E7”.
There is also a reverse situation – the fan does not turn on. This behavior can be considered normal when the power level of the hob is at its minimum. It should turn on when the air temperature around it rises. above 50°С. A test program is run to test the fan. If it shows that the mechanism is out of order, then it needs to be changed.
High power burner does not turn on
There are situations when you want to turn on the most powerful burner, with a maximum power of 3 kW, but nothing happens. This is considered normal if other cooking places are working and the temperature near the induction coil unit exceeds 780 degrees. So that when you turn on the most powerful burner to exclude unit overheating, it is blocked. When the cooking places have cooled down, the lock will be released and the coil will turn on. But, if the burner does not turn on, you will have to change the control unit.
The cooker switches off automatically
The induction cooker can turn off automatically in the following cases:
- if you plugged the unit into the network, and within 10 seconds did not perform any actions on the touch panel, for example, did not select a hob, did not set the power, and so on;
- the operation of the burners lasts more than 2 hours;
- if the electronic timer has worked, on which the time for turning off the stove was set.
In other cases, when the stove can spontaneously turn off, you cannot do without the help of a qualified specialist, as it will be necessary control unit replacement or the entire induction coil unit.
The hob hums during operation
The induction hob can make various noises during operation, and they can occur for the following reasons:
- the device may hum if it is placed on the hob saucepan with a thin bottomor excessive power is set;
- the stove often hums or whistles when a small saucepan is placed on a large burner;
- vibrations can occur at the junction of different materials when the bottom of the pan consists of several layers;
- The intensity of the noise depends on the amount of dishes on the hob.
With a constantly sounding beep, it can be assumed that the reason that it does not turn off is in the control unit, which is repaired only by replacing it with a new one.
Useful tips for the master
For faster repair in conditions of inaccurate fault detection (and not only), you can give some useful tips. Firstly, burner generators are designed as an independent module. They are filming. By changing the generators in places (from one burner to another), you can quickly understand what is broken, the coil or its high-frequency voltage blog.
The second tip will sometimes help save a lot on repairs. In slabs that are not cheap or rarely found due to the lack of distribution on the market, the burnt part can be unique and very expensive. And its rarity further raises the cost of replacement. But it is not necessary to install an element that is indicated on the circuit diagram of the plate. There is electronic components compliance database. It can be easily found on the Internet at the request of Datasheet or on thematic forums. It will find a more inexpensive or commercially available analogue of the part that is needed to be replaced with an induction cooker.
If the cause of the breakdown has not been established, or if there are difficulties about how to purchase and install failed modules, then it is better to turn to professionals to repair the induction cooker. You should also remember about warranty service, the right to which you can lose if you open the unit yourself. The induction cooker is a “smart” technique and requires careful observance of the operating rules.