The constant discharge of water into the sewer immediately after the start of collection or during the washing process most often indicates a violation of the tightness of the drain system or a critical error in the liquid level sensors in the chamber. Unlike regular pauses, when the equipment collects and drains water for rinsing, here there is uncontrolled operation of the pump, which does not allow the device to collect the required volume to start the main cycle. If you notice that The dishwasher constantly drains water into the pan or directly into the sewer; this cannot be ignored, as this can lead to flooding of the kitchen or failure of the heating element due to dry operation.
Primary diagnosis requires a visual inspection under the kitchen sink and checking the condition of the drain hose, since often the cause lies in a simple incorrect installation of communications. The pump can operate continuously, trying to pump out liquid that flows by gravity from a sink or siphon if there is no special bend in the pipe. In more complex cases, when external factors are excluded, the problem is localized inside the housing, where electronic components or mechanical components responsible for holding water in the tank could fail.
The main reasons for the continuous operation of the drain pump
The most common technical reason why dishwasher cannot draw water and constantly pumps it out, the check valve is faulty or there is a blockage in the filtration system. When this valve does not close tightly, water from the sewer system or siphon freely flows back into the chamber of the machine. The liquid level sensor detects the presence of water and gives a command to turn on the pump, but since the valve is open, water continues to flow, creating a closed cycle of endless draining.
The second important group of reasons are problems with aqua sensor or a pressure switch. This sensor is responsible for monitoring the water level in the tank. If its contacts are oxidized, the membrane is stuck, or the wiring is broken, the control module may receive a false signal that the chamber is full. In response to this, the “brain” of the machine starts an emergency pumping mode, which does not stop until the malfunction is eliminated or the power supply is turned off.
⚠️ Attention: Constant operation of the drain pump without interruption can lead to overheating and burnout of its motor. If a symptom is detected, stop using the device immediately.
It is also worth considering the possibility of software failures in the control module, especially after power surges in the network. The electronics may become stuck in the drain cycle without moving to the next stage of the program. In rare cases, the cause is a leak in the hose leading from the tank to the pump, causing water to flow into the pan, activating the leakage protection system. AquaStop.
Diagnostics of the drain system and check valve
To begin the inspection, it is necessary to dismantle the drain hose and carefully inspect the place where it is connected to the sewer pipe or siphon. This is where it is located check valve, which in good condition allows water to pass in only one direction. If fat, food debris or scale has accumulated in its cavity, the mechanism may jam in the open position. Cleaning this part often solves the problem without calling a technician.
Check the hose itself for kinks, cracks or mechanical damage that could have formed during operation. If the hose is connected to the common pipe too low, without creating a water seal, this may cause gravity to drain water from the sink into the dishwasher. In such cases, water flows by gravity, and the pump pumps it out, creating the illusion of equipment failure.
| System element | Symptom of malfunction | Elimination method |
|---|---|---|
| Check valve | Water flows back into the chamber | Cleaning or replacing the valve |
| Drain hose | Cracks, bends, low connection | Replacing the hose, changing the connection height |
| Sink siphon | Clogged dishwasher drain | Cleaning the siphon and outlet |
| Pump | Humming, no pumping | Foreign object removal or replacement |
Pay special attention to the height of the drain hose connection. According to the technical regulations of most manufacturers, the point of insertion into the sewer should be at a height of 40-60 cm from the floor. If the hose lies on the floor, the effect of communicating vessels is created, and dirty water from the sewer will constantly flow into the tank of the machine.
☑️ Checking the drainage system
Malfunctions of level sensors and control module
If the mechanical part of the drain system is working properly, the problem may lie in the electronics. Pressostat (water level sensor) transmits information about the amount of liquid in the tank to the electronic module. If this unit malfunctions, the machine may “think” that the tank is full and continuously turn on the drain pump. The test is carried out using a multimeter: the resistance of the sensor contacts is measured at different pressure levels.
The control module can also be the source of the problem, especially if the board has been exposed to moisture or has experienced power surges. Burnt tracks or swollen capacitors on the board can give a false command to pump out water. Some models Bosch or Siemens this is manifested by error codes indicating problems with the AquaStop system, even if there is no leak in the pan.
⚠️ Attention: Repairing the electronic control module requires professional skills and special equipment. Do not try to solder the board yourself without experience.
The water turbidity sensor (aqua sensor) is also involved in the decision-making process about drainage. If it is dirty or faulty, it may mistakenly detect the water as dirty and initiate a continuous draining and collection of clean rinse water in what appears to be an endless loop.
Clogged filters and internal lines
A common but common scenario is severe contamination of the filtration system. If coarse filter clogged with food debris, fat or bones, water cannot circulate normally inside the chamber. The system may interpret the lack of circulation as the need to drain dirty water, when in fact it is simply not passing through the pump.
The blockage can be localized not only in the filter, but also in the pipes leading to the pump. Small objects such as toothpicks, glass shards, or fruit pits often become stuck in the pump impeller or just before the drain valve. This interferes with the normal operation of the mechanism and can block the valve in the open position.
To eliminate it, you need to remove the baskets, remove the bottom filter and thoroughly rinse all elements under running water using degreasers. It is also recommended to check the pipe connecting the tank and the pump for the presence of foreign objects.
Problems with tightness and the AquaStop system
Leak protection system AquaStop (or its analogues from other brands) includes a tray located in the lower part of the body. If there is water in this pan, a special float rises and closes the contacts, forcing the machine to turn on the drain pump in emergency mode. In this case, the intake of new water is blocked, and the machine will only work to drain as long as there is moisture in the pan.
The reason for water getting into the pan may be a microcrack in the tank, a burst clamp on the pipe, or a simple overflow over the edge of the chamber due to the use of an unsuitable detergent. Even a small amount of water in the pan activates the protection. To verify this, you need to remove the bottom panel of the machine and look into the pan.
If the pan is dry, but the machine continues to drain water, the float mechanism itself may be faulty or the contacts of the leak sensor may have oxidized. In some cases, it is enough to dry the pan with a hairdryer to get the machine out of emergency mode, but this is a temporary measure if the cause of the leak is not eliminated.
Algorithm for self-troubleshooting
For effective repairs, follow the step-by-step instructions, eliminating simple causes before disassembling complex components. Start with a visual inspection and cleaning of accessible elements, since in 60% of cases the problem is solved at this stage. If simple methods do not help, proceed to diagnosing the electronics and replacing parts.
- Unplug the dishwasher and turn off the water supply.
- Check that the drain hose is connected correctly and the height of its insertion.
- Clean the filters and inspect the chamber for debris.
- Check the non-return valve at the sewer connection.
- Remove the bottom panel and check the tray for water (AquaStop activation).
- Ring the sensors and check the integrity of the wiring with a multimeter.
If after all checks the cause is not found, it is likely that the drain pump needs to be replaced or the control module repaired. In this case, it is advisable to contact a service center, especially if the equipment is under warranty.
Prevention and operating rules
To avoid a repeat situation where dishwasher constantly drains water, you must follow the operating instructions. Clean the filters regularly to remove food debris, even if they appear clean. Fatty deposits tend to accumulate and, over time, disrupt the functioning of valves and sensors.
Use only high-quality detergents designed specifically for dishwashers. Hand wash gels or regular soap cause excessive foaming, which can lead to water overflowing into the pan and false activation of the protection system.
Periodically run the machine empty with citric acid or a special cleaner added to remove scale and grease from the internal lines. This will help maintain the throughput of the pipes and the serviceability of the valves at the proper level.
Frequently asked questions (FAQ)
Why does the dishwasher fill with water and immediately drain?
This is a classic symptom of activation of the leakage protection system (AquaStop). Water has entered the housing pan, and the machine is trying to pump it out, blocking the intake of new water. It could also be due to a faulty check valve that allows water to flow back from the sewer.
Could a clog cause the machine to constantly drain water?
Yes, a severe clog in the filter or drain hose can interfere with circulation. However, more often when there is a blockage, the water simply remains in the tank. Constant draining is most often associated with problems with valves or sensors, but you need to check the filters first.
What to do if the leak indicator is on?
It is necessary to disconnect the device from the network, turn off the water and remove the bottom panel. If there is water in the tray, wipe it dry. If after switching on the error repeats, it means that the leak continues or the sensor in the pan is faulty.
How to check the dishwasher check valve?
You need to remove the drain hose from the siphon. There is a valve inside the plastic tip. Try blowing into it: the air should only flow in one direction. If it blows in both or does not blow at all, the valve is faulty or dirty.
How much does it cost to replace a drain pump?
The cost depends on the car model and region. The pump itself costs from 1,000 to 3,000 rubles, plus the cost of the technician’s work. In some cases, the pump can be disassembled and cleaned of debris, which will extend its life.