Dishwasher won't turn off

A lot has been reported about malfunctions, the characteristic symptom of which is that the dishwasher does not turn on. But there are also opposite symptoms of failure. The dishwasher starts normally and starts working, but then for some reason it cannot stop. Moreover, it is possible to stop the car only by unplugging the power cord from the socket. This problem is often found in Bosch dishwashers and other models, so we decided to take a closer look at the possible causes of the problem and how to fix them.

The pump does not turn off

The dishwasher pump is designed to pump waste water out of the washing tank. During the entire washing cycle, dirty water can be removed repeatedly, while the program algorithm specifies at what point the control unit should give the command to turn the pump on and off, as well as the duration of operation of the drain pump.

It is very important at what moment the command to turn on the pump is given. The control unit must collect information from all sensors and, based on this information, make a decision to turn on the pump or not. If the pump runs continuously and does not turn off, this means that:

• the electrics or electronic module are faulty - commands are not given to the pump or they do not reach the pump;
• the control module receives information from the pressure switch about excess water in the Bosch dishwasher;
• the machine is not installed level (some models of dishwashers are sensitive to slopes and do not want to work normally even with a slope of 5⁰);
• the Bosch dishwasher is not connected to the sewer correctly, which leads to a “siphon effect” (backflow of dirty water into the machine), while the pump is forced to constantly try to pump out the water;
• the pump itself is faulty.

There are also optional reasons for the constant operation of the pump, for example, in the event of a leak in the inlet hose or pipe. But in such a situation, it is quite difficult not to understand why the drain pump works strangely, because water will flow from under the car, and it will flow heavily.

Aquastop hose for dishwasher can prevent this from happening, but then the pump won’t show itself. Even if your dishwasher does not have Aquastop protection at all, a slight leak in the hose will not affect the operation of the pump in any way; in order for the drain pump to react, a strong pressure drop is required, which can cause either a water hammer or a rupture of the hose or pipe.

For your information! Full Aquastop protection will protect the dishwasher from leaks of any nature, but you still need to be careful.

The symptom of a breakdown boils down to a constant hum emitted by the pump, regardless of whether the washing program is running or not. Moreover, if you turn off the power to the dishwasher (by unplugging the power cord), then when you turn it back on, the pump will still continue to operate continuously.

The procedure for eliminating the breakdown will depend on its nature, let's start with a simple reason: when a Bosch dishwasher is incorrectly connected to the sewer pipe, what do we do?

1. Unscrew the drain hose from the siphon or sewer pipe.
2. We check that the length of the hose does not exceed 2 m.
3. We check the bend and height of the hose connection (the height of the connection point from the floor should be no more than 50 cm).
4. We redo the connection to the sewer and screw the hose back on.

After this, the pump should stop being capricious and start working normally. If, after fixing the connection to the sewer, the Bosch dishwasher continues to use the pump excessively, you can look at how this machine is installed on the floor. Bosch brand dishwashers are not too demanding on the surface on which they are installed; even large slopes of 8-10 are allowed⁰ . Electrolux brand machines are more capricious, so they need to be installed level on a hard, reliable surface.

If the dishwasher is installed well, then most likely the problem has arisen with one of the units, the sensor, or the control module in general, which in itself is not very good. Mentally, you need to prepare for the costs and start checking the electrics and electronics of the car.

By the way, you don’t have to do it yourself; if serious problems arise with the dishwasher’s electronics, it’s better to contact a specialist. This way there is less chance of causing further damage to the dishwasher. But if you are determined to see it through to the end, at least read the advice of professionals.

The washing program does not start and does not turn off

If the Bosch dishwasher (or another) does not respond to user actions after turning on, that is, most of the buttons do not work and it is impossible to turn on any washing program, at the same time, it is also impossible to turn off the machine from the button - this indicates a malfunction of the control panel. More precisely, a problem arose with one of the control triacs or the contacts of one of the buttons. If several buttons do not work at once, then most likely the problem is the triac.

For your information! A triac is a special semiconductor part that is installed on the control board of a Bosch (and other brand) dishwasher. Another name is symmetrical triode thyristor.

To check and replace a triac, you will need minimal knowledge of semiconductor circuits and the ability to work with a soldering iron and a multimeter. First, let's set up the multimeter.

• Turn on the device and set it to voltmeter mode.
• Set the minimum value in Volts.
• We connect the multimeter probes to each other and check how the device works; if everything is fine, we move on to the next step.
  

Now our task is to get to the control board. Turn off the power to the dishwasher and open its door. There are small fasteners at the ends of the door and on the inside; they need to be unscrewed while holding the door in the open position. The inside of the door will come off like a sandwich, revealing the control board. Next we do the following.

1. We find triacs on the control board (see photo) and check them one by one using a multimeter.
2. If you find a faulty part, carefully unsolder it and remove it.
3. Take the broken part as a sample and purchase a similar one in the store or take it from a non-working device.

Important! It is necessary that the numbers and markings on the faulty part and the new one match.

4. Very carefully, so as not to damage the tracks, solder the new part in place of the old one.

Now we put the control board in place, assemble the door, connect power to the dishwasher and check the operation. After these simple manipulations, the dishwasher should turn on and off normally.

The washing program is stuck

The dishwasher often does not turn off due to a system error.System errors are written in the program of the machine control module; they help to carry out self-diagnosis and inform the user about breakdowns of various natures. A system error that appears on the dishwasher display stops its operation, and in some cases does not even allow it to be restarted using the on/off button. Turning the machine on again does not solve the problem, the error appears again.

A striking example would be error e22 for Bosch dishwasher. This error occurs if the user of the dishwasher forgets to clean it, the filter becomes clogged, the sensors are triggered and the control module blocks the operation of the entire machine until the blockage is cleared. In this case, the dishwasher does not turn off and does not react at all to user actions.

If the dishwasher does not turn off due to one of the many system errors, there is only one cure - find the cause of this error and eliminate it. Only in this case will you forget what it’s like to watch the dishwasher not turn off.

To summarize, we note that if the dishwasher does not turn off, then this is an alarming symptom that accompanies a more serious problem, usually a breakdown. It’s bad if we are talking about a breakdown of the pump or, even worse, the control module, but it happens that the ability to control the dishwasher is affected by a simple clogged filter. This is another reason to remind dishwasher users of the need to constantly care for their “iron assistants.”

1 reader comment

1. 04/30/2020 at 18:29

   alek:

   Bosch 3 in 1 dishwasher stops turning off. There is one minute left and the machine does not finish, but continues to work. What is the reason?

   Answer