Causes of stagnant water at the bottom of the dishwasher

Dishwashers utilize water in a cyclical manner: it undergoes spraying, followed by filtration upon removal, and subsequently, it is recirculated from the sump. At the conclusion of the washing procedure, the polluted liquid ought to be completely expelled; however, occasional malfunctions occur wherein the dishwasher fails to drain the water. Discovering the root cause and remedying the malfunction becomes imperative.

The principle of operation of the device

Water is introduced into the dishwasher through the inlet valve, which is a single type for this particular model. It then fills the tank to a specific level and is pumped by the recirculating pump into the spray arms. As the water is under pressure, it creates a circular motion of the spray arms, effectively removing food residues. To ensure proper dishwashing, the water is heated to the maximum temperature set for this model using a special heating element. Afterward, the water is collected at the bottom of the machine, filtered, and then used for a new cycle.

Once the dishwashing process is complete, the drain pump immediately removes all liquid from the machine and directs it into the sewage system. If any water remains stagnant on the bottom, there may be a clog in the system.

1. Water is drawn into the main tank.
2. Regulating the sump level during the process of draining contaminated water.

The main control panel utilizes the data it receives in multiple ways, and this is where it receives notifications regarding any malfunctions that may arise.

Possible causes

Drainage issues in a dishwasher often arise from a blocked filter or a twisted drain hose – these problems can be resolved without the need for a specialist. If a specific component or the entire system breaks down, then professional assistance is required.

What causes water to accumulate in the dishwasher? There are various reasons:

• The coarse or fine filters may be clogged;
• There might be a simple kink in the drain hose;
• The drainage system could be blocked;
• The drain pump may be malfunctioning or clogged;
• The water level sensor could have failed;
• There might be a malfunction in the program module.

Clogged filters

An accumulation of water at the bottom of the dishwasher is often caused by a blocked filter, so it is important to start by checking the various cleaning systems. If there are multiple food residues on the dishes, the filters can become blocked quite quickly and will require cleaning. Fortunately, if you have a Bosch brand machine, you won’t encounter major issues when it comes to cleaning the filter system.

A piece of advice for the hostess! To prevent the machine from getting clogged, make sure to remove any food residue from the plates before placing them in the baskets. This simple step will help prolong the smooth operation of your dishwasher.

The housing for the filter is situated at the machine’s lower part and can be effortlessly detached. Afterward, rinse it thoroughly under a stream of water and reinstall it securely. Pour 2-3 cups of water into the lower area and activate the pump – the water will drain out, thereby resolving the issue.

The drain hose is clogged or blocked

Located at the rear of the unit, the hose connects the drainage system to the sewer. If it becomes crushed, the water will not be able to drain properly. To resolve this issue, start by disconnecting the machine from the power source and tilting it away from the wall. Conduct a visual inspection of the hose and address any detected malfunctions.

In some cases, the hose may become clogged with debris from the inside, preventing water from escaping the machine. To fix this problem, disconnect the hose from the sewer and place it in a prepared bucket. When you activate the dishwasher’s drain function, water should flow out with pressure. This indicates that the clog is located at the connection point between the hose and the sewer. If the water pressure is weak, check for any obstructions within the hose and clean them out.

Dishwasher drain hose

Drainage system and drain pump

The drainage system is inspected in the same manner as the hose: if there is pressure, everything is functioning properly. If the water jet is weak, it indicates the need for cleaning. The drain pump, on the other hand, presents a more challenging task. In certain dishwasher models, the pump is situated in a hard-to-reach location and can only be disassembled by professionals. However, in Bosch dishwashers, the pump is conveniently positioned and can be dismantled by the user. It is advisable to check the pump for blockages and clean it. Additionally, the inner impeller should be examined using a pencil. Extreme caution must be exercised to prevent any damage to the impeller and to avoid injury from small fragments of dishes that can cause clogging.

Dishwasher circulation pump

The operation principle of the pump is similar to that of a washing machine:

• It has an induction motor with two coils;
• There is a magnetic rotor;
• The water is expelled by a cross-shaped impeller that rotates strongly;
• The power is supplied from a standard 220 V electrical outlet.

After that, reinstall all the components and test whether the pump is able to pump out water. If it does, the repair is complete. However, if there is still standing water at the bottom of the dishwasher, it may indicate a more serious issue that requires the expertise of a professional technician.

Pressostat failure

If you are unable to remove the water, it is possible that the issue lies with the level sensor. To determine if this is the case, you will need to disassemble the pressure chamber – a compact plastic box that is installed upside down. Next, blow into the transparent tube and then reconnect it. If you hear a clicking sound, it indicates that the sensor is functioning correctly.

If you have the necessary knowledge and equipment, you can also trace the sensor circuit diagram. After completing these steps, the water should drain without any issues.

Failure of the electronic system

We have examined the main methods of draining water from various faults in the dishwasher, but there are additional factors that can cause water to accumulate at the bottom of the machine – for instance, a malfunction in the program module. This module regulates the processes that the machine is meant to perform, and it is responsible for issuing commands for all systems to carry out their functional duties. If it becomes faulty, it can lead to disruptions in the proper functioning of the household appliance.

If, despite checking all possible causes of failure, water continues to collect at the bottom of the dishwasher after the end of the cycle, it is recommended to promptly have the module diagnosed at a service center.

In the case of an error, modern household appliances are equipped with displays that show error codes. By referring to the instruction manual, users can easily decode these error codes and follow the troubleshooting recommendations. If the manual does not provide a solution, users can always turn to the Internet for answers to frequently asked questions.