A Bosch dishwasher does not drain water and stops the wash cycle, most often due to a clog in the filter assembly or a blocked drain pump impeller. An error code may appear on the display. E09, E24 or E25, indicating problems with drainage. In some cases, the equipment simply freezes at the draining stage, emitting a characteristic humming sound, but not pumping liquid into the sewer.
Ignoring this malfunction leads to dirty water with food residues remaining in the tank, which provokes the appearance of an unpleasant odor and the growth of bacteria. If you ignore the symptoms, circulation pump may start to idle, which can lead to overheating. The owner needs to conduct an initial diagnosis to understand whether simple cleaning or calling a technician for replacement is required drain pump.
Fixing the problem on your own is often possible if the cause is a small bone, a lemon seed, or a crumpled corrugation. However, before starting any disassembly or cleaning work, be sure to unplug your Bosch dishwasherby removing the plug from the socket. This is a basic safety rule that will protect you from electric shock when working with moisture or electrical components.
Deciphering error codes for problems with drainage
Modern dishwashers Bosch equipped with a self-diagnosis system that displays alphanumeric combinations when failures are detected. Understanding these codes allows you to immediately narrow down the troubleshooting area and not have to guess why there is water. Most often, drainage problems are accompanied by E-series codes related to the operation of the drainage system.
Code E09 indicates a malfunction of the heater or problems with the level sensor, which indirectly affects the drain cycle, since the machine cannot complete the program. Errors E24 and E25 more specific: they signal that the filter is dirty or the drain pump is blocked. If the symbol of a tap or shower head flashes on the screen in combination with the letter E, this is a direct signal to check the water path.
⚠️ Attention: The constant appearance of an error code after restarting the program indicates a serious technical malfunction that cannot be ignored.
The table below provides a breakdown of the main codes associated with the inability to drain water, and their probable causes:
| Error code | Description of the problem | Probable Cause | Solution method |
|---|---|---|---|
| E09 | Heater/sensor malfunction | Open circuit, scale on heating element | Checking contacts, replacing heating elements |
| E24 | Filter clogged | Food waste in mesh | Cleaning the filter assembly |
| E25 | Pump blocking | Foreign body in the impeller | Removing and cleaning the pump |
| E15 | Leakage into the sump (AquaStop) | Water in the bottom of the hull | Drying, leak detection |
Primary diagnosis and check of the drain hose
Before disassembling the inside of the dishwasher Bosch Serie 4 or older models, external factors must be excluded. Often the reason is simple: the drain hose is kinked, crushed by heavy furniture, or clogged with debris at the connection to the sewer. A visual inspection of communications is the first step, which takes no more than five minutes.
Check for kinks in the hose, especially if the machine is built into a narrow kitchen unit. It is also worth inspecting the place where the sink siphon is inserted: if the pipe is clogged with fatty deposits, the water will physically not be able to go into the sewer, creating back pressure. In such cases, the dishwasher hums, trying to push water through, but to no avail.
- 🔍 Inspect the drain hose along its entire length for kinks and squeezing.
- 🚿 Disconnect the hose from the siphon and check the permeability by blowing it or spilling water.
- 🧼 Clean the outlet in the sewer pipe from fat plugs and plaque.
If the hose is long and laid in a complex way, a water seal or dirt accumulation may have formed at its lower point. It is recommended to disconnect the hose from the machine and the sewer in order to thoroughly rinse it under strong water pressure. Sometimes a layer of fat accumulates inside, which narrows the opening, reducing performance. drainage system.
Cleaning the filter system and chamber bottom
The most common reason why a Bosch dishwasher does not drain is due to dirty filters. At the bottom of the washing chamber there is a coarse and fine cleaning system that traps food residues. If this unit is clogged, water cannot enter the pump and the drain cycle becomes impossible.
First you need to remove the lower basket and get to the bottom of the tank. There you will see a flat mesh filter and a cylindrical fine filter. They need to be carefully unscrewed counterclockwise and removed. Often a mush of grease and small debris accumulates underneath them, which should be removed with a soft brush and detergent.
☑️ Filter cleaning checklist
After washing the filters, carefully inspect the hole leading to the pump. A bone, a toothpick, or a piece of glass could have gotten in there. If you see a foreign object, it must be removed with tweezers or your fingers (being careful). Cleanliness of this assembly is critical for proper operation. circulation pump and the entire drainage system.
Checking and servicing the drain pump
If the filters are clean and the water is stagnant, the problem may lie in the drain pump (to the pump). In dishwashers Bosch it is located under the filter system. The pump impeller may be blocked by a small object that has passed through the filter, or the motor may have failed.
To get to the impeller, you need to remove the filter and look into the hole. Try gently turning the impeller with your finger or a thin screwdriver. It should rotate freely, with slight resistance from the magnets. If you feel jamming or hear a crunching noise, it means that debris has gotten inside or the engine bushings have worn out.
⚠️ Caution: When removing foreign objects from the pump, be extremely careful not to damage the plastic impeller blades.
Sometimes the pump hums, but does not pump water. This may mean that the motor winding is intact, but the mechanical part is jammed, or the start capacitor has burned out. Some models Bosch Silence Plus Access to the pump for replacement requires partial disassembly of the housing, so if simple cleaning does not help, a more in-depth repair may be required.
How to replace a Bosch drain pump
To replace, you will need to remove the side wall of the case (usually the left one when viewed from the front). Disconnect the clamps from the pipes leading to the pump and disconnect the electrical connector. The new pump is installed in the reverse order, making sure that the seals are positioned correctly.
Analysis of the condition of pipes and internal connections
Inside the dishwasher body, water circulates through a system of rubber pipes. Over time, they can become clogged with grease deposits, especially if you rarely use grease removers or wash dishes at low temperatures. A blockage may occur at the connection between the pump and the tank or in the corrugated hose.
To check the internal pipes, it is often necessary to remove the side panel of the housing. Visually inspect the hoses for kinks, cracks, or bulges. If the hose feels hard and clogged, it is best to replace it. Also check the connections for leaks that could cause the system to trip. Aquastop.
- 🔧 Remove the side wall of the case to access internal communications.
- 💧 Check the elasticity of the pipes and the absence of hard plugs in them.
- 🔗 Make sure the clamps are securely fastened and there are no water leaks.
It is important to check the check valve if it is included in the design of your model. It prevents dirty water from flowing back into the machine. If the valve is stuck in the closed position, the water will also not be able to escape. It must be removed, washed and checked for freedom of movement of the moving part.
To prevent grease build-up, once a month run an empty wash at 70°C with the addition of citric acid or a special dishwasher cleaner.
Electronic diagnostics and error reset
After all mechanical cleaning and checks have been carried out, it is necessary to reset the error in the memory of the electronic module. Dishwashers Bosch can store a fault code, blocking programs from starting. To reset, you usually just need to turn off the machine with the power button and turn it on again by selecting the drain program.
If the error repeats, the problem may lie in the electronics: the water level sensor (aqua sensor) or the control module itself is faulty. The level sensor can “lie”, telling the controller that there is no water in the tank, although there is some, or vice versa. Diagnostics of such components requires a multimeter and skills in working with electrical circuits.
⚠️ Attention: Do not try to repair the electronic control module yourself without the appropriate qualifications, this may lead to complete failure of the equipment.
In some cases, rebooting the system helps by holding the "Start/Pause" button for a long time (about 5-10 seconds) or a special combination of buttons, depending on the model. If after all the manipulations the Bosch machine still does not drain water, and no mechanical obstacles are found, it is advisable to contact a service center for professional diagnostics electronic board.
90% of drainage problems in Bosch dishwashers are solved by thoroughly cleaning the filters and checking the pump impeller for foreign objects.
Frequently asked questions (FAQ)
Why does my Bosch dishwasher hum but not drain?
A humming sound indicates that the sump pump motor is trying to operate but cannot turn the impeller. Most likely, it is blocked by a foreign object (bone, glass, bone) or jammed due to wear on the bushings. It is also possible that the starting capacitor may fail.
What does the flashing salt or rinse aid indicator mean when there is a drain error?
The salt and rinse aid indicators may flash as part of a general error signal. In combination with codes E24/E25, this confirms a drainage problem. The machine cannot complete the rinse and drain cycle, so it signals an incomplete process in all available ways.
Is it possible to use a dishwasher if it does not drain completely?
Strongly not recommended. Remains of dirty water will lead to damage to clean dishes during the next wash, the appearance of a persistent unpleasant odor and corrosion of internal elements. In addition, this may cause the heating element to burn out if it is not immersed in water or, conversely, overheats.
How often should you clean the filters in a Bosch dishwasher?
It is advisable to rinse coarse filters after each washing cycle, removing large food residues. It is recommended to deep clean the filter assembly using a brush and detergent at least once a week to prevent the formation of grease plugs.
Error code E15 is constantly on, what should I do?
Error E15 means the leakage protection system (AquaStop) has been activated. Water has accumulated in the pan of the car. You need to unplug the device, turn off the water and let the car dry for 24 hours. If the error returns immediately after switching on, it means that the leak persists and a search for a damaged pipe or seal is required.