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Dishwasher Bosch does not heat water - what to do?

PMM Bosch does not heat waterIn the event that the Bosch dishwasher does not heat the water, there is no need to rush it to disassemble in order to check the heating element. For the layman for some reason, it is obvious that if the machine refuses to heat the water, it means that the heater is to blame. In reality, the reasons may lie in something completely different, but of course the heating element cannot be ruled out.

Damage or not?

Before rushing to disassemble the Bosch dishwasher, there are a few obvious things to check. Firstly, if the dishwasher is completely new and has recently been put into operation, you need to look at how it was connected to the water supply. The fact is that Bosch dishwashers have two outlets for the inlet hose: under hot water and under cold. If the entrances are mixed up during installation, then the machine will think that hot water comes in instead of cold water and will not heat it. If you connect the inlet hose correctly, the problem will be resolved.

The machine may stop heating the water if the user made mistakes during its operation. In particular, if the wrong program was selected or, most likely, the garbage filter was not cleaned in time. Blockages in the system can disrupt the circulation of water, which in turn leads to the fact that the machine begins to wash dishes with interruptions and cold water. The conclusion is: you need to look at the instructions and make sure that you are choosing the right washing program. In addition, you need to clean the trash filter and make sure that there are no clogs deeper.

Having unscrewed the garbage filter, look into the formed niche and if you find dirt there, remove it.

If you are sure that you did not make operational errors, it means that, most likely, some kind of breakdown "crawled out". There are a lot of possible options, let's try to list the main ones.

  1. Faulty thermostat. Typical "sore" dishwasher brand Bosch. Due to a faulty thermostat, the control module receives incorrect water temperature information. In this case, the module either does not turn on the heating element at all and then the water remains cold, or it drives it constantly, and then the machine always rinses the dishes with boiling water.
  2. Defective heater. After reading the article Spare parts for Bosch dishwashers, you can make sure that the heating element in Bosch is connected to the recirculation pump. Therefore, if the heater fails, the entire assembly has to be changed. Fortunately, the heating elements of these machines do not break often.
  3. The control module is out of order. If the tire responsible for the heating element burns out, then this will be enough so that the heater does not turn on and the water remains cold.
  4. There are problems with the wiring. Conductors supplying the recirculation pump with a heating element and thermostat can also cause dysfunction of these parts. It is enough to rub one wiring or jump out of the chip, the water will stop heating.

Breakdown Search AlgorithmTEN dishwashers

First you need to disassemble the dishwasher to gain access to the details of the pallet. You can read about how to do this in the article. How to fix Bosch Dishwasher Error E14, now we will not focus on this.

Having removed the Bosch dishwasher tray, you should take a multimeter and check all the details from the list of suspects in turn. We will not go to the control module, because its repair and diagnostics require special knowledge. First, we disconnect the chip with wires from the recirculation pump, and then we measure the input resistance. The resistance of a working pump along with a heating element will be about 25 ohms, depending on the specific model, but not lower than 18 ohms. Significantly lower resistance values ​​indicate that the part is broken and needs to be changed.

Next, check the thermostat. We also disconnect the wires from it and make measurements.The input resistance of the thermostat at room temperature is 6000-4700 Ohm, if it shows less, then the problem lies in the thermostat. If both of these details are not suspicious, you should pay attention to the wiring. Start with a visual inspection. Burned, frayed or dropped out wiring will not escape the careful look. Do not be lazy to spend a little more time looking at the wiring.

If visually it was not possible to detect damage, it is worth again armed with a multimeter and check each wire for a breakdown. It may well be that somewhere the postings broke under isolation, which created a lot of trouble for you. If faulty wiring is found, it must be replaced.

Do it yourselfdamaged wires

What to do when it is possible to detect a breakdown? Some beginners "homemade" offer to restore the heating element in the recirculation pump. This repair option seems to us very doubtful, therefore we do not see any other solution than to change the entire assembly. To begin with, we look at the part number and we order the exact same number on the Bosch website by this number, it will turn out to be 15-20% cheaper. We disconnect the old pump, and put a new one in its place, nothing tricky.

We do the same with a thermostat, but if you suspect a malfunction of one of the control board buses, feel free to call the service center. Independently diagnose a breakdown of the control board, and then carry out its high-quality repair under the power of units. Do not risk the expensive part.

So, to determine why the Bosch dishwasher does not heat water in most cases, you can do it yourself. At the same time, you can really save several thousand rubles, especially if you carry out diagnostics and repairs very carefully and thoughtfully. Good luck


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