The appearance of a fault code on the display or the flashing of indicators in a certain sequence always takes you by surprise, especially when water and linen are left in the drum. Code. E21 stamp-making Bosch signaling a critical problem with the water drainage: the electronic control system recorded that the liquid does not leave the tank in the time allotted by the program. This is most often done during the spin or rinse phases, when the pump must be operating at maximum power.
Do not panic and immediately call the master, since in most cases the problem lies in a banal blockage or a foreign object that is easy to remove yourself. However, you can not ignore the signal, since the constant operation of the pump engine idle or with a blocked impeller can lead to its burnout. In this article, we will discuss in detail the mechanics of the process, diagnostic algorithms and step-by-step actions to eliminate the malfunction.
Modern automation Siemens and Bosch It is arranged so that when blocking the drain, the machine can try to start the pump several times, making pauses. If you hear a buzzing sound but the water is still, or if there is silence where the sound of the engine is running, then it is time to intervene. Let’s see what exactly happened inside your plumbing system.
Mechanism of error and system diagnostics
Mistake. E21 is formed by the control module based on the readings of the water level sensor (pressostat) and the timer. The logic of the controller is simple: after the command to drain, after a certain period of time (usually a few minutes), the water level in the tank should fall below the critical mark. If the pressostat reports that the water is still in the tank, the system fixes the error and stops the wash cycle, often leaving the door locked for safety reasons.
There are two main scenarios that lead to this outcome. The first is a mechanical obstacle: the impeller pump can not rotate because of a coin, bone from a bra or a lump of hair. The second scenario is an electrical fault, when the drain-pump Failed, the engine winding burned or contact in the power chain was disrupted. Also, it is impossible to exclude a blockage in the highway itself or the sewer siphon.
For the initial diagnosis does not require complex equipment. You need to listen carefully to the sounds that the machine makes when trying to drain. A buzz without water movement indicates that the motor is getting power and trying to work, but something is hindering it. Complete absence of sound when activating the drain mode more often indicates a circuit break, a burnt engine or a malfunction of the control module that does not supply voltage to the pump.
⚠️ Before starting any diagnostic work, be sure to disconnect the washing machine from the electrical network. Water and electricity are a dangerous combination, and the drain system can remain voltage even after the device is turned off.
Initial inspection and cleaning of the drain filter
The most common reason for code E21 - it's a clogging of the drain filter. This element is designed to delay large items (buttons, coins, pile) so that they do not damage the impeller of the pump. Over time, the filter clogs and water stops passing through it at the required speed. Cleaning the filter is the first procedure that any drain-related repair should begin with.
To access the filter on the machines Bosch Usually a special door is provided at the bottom of the case, often hidden behind a decorative panel or located in the basement. Before you unscrew the plug, be sure to prepare a flat tray or rags, since residual water will leak out of the hose, which can be quite a lot (up to 1-2 liters). Unscrew the plug slowly, controlling the flow of fluid.
After removing the filter, carefully examine it and the inner cavity of the pump. Often it is there that lost socks, small toys or dense lumps of dirt are found. Clean the filter under the water jet using a brush to remove plaque. Also check if the impeller of the pump rotates freely, if it can be reached with a finger. It should rotate easily, without jamming and extraneous sounds.
☑️ Cleaning the drain filter
Analysis of the drain hose and sewerage status
If the filter is clean, but the error E21 If the problem does not go away, it may be hidden deeper in the hydraulic system. The drain hose can be bent, transmitted by the body of the machine or clogged at the connection point to the sewer. Often users forget that the pipe connecting the tank and the pump, or the area between the pump and the siphon, can also accumulate deposits.
Particular attention should be paid to the place of connection of the hose to the sewer pipe. If the connection is not made correctly or the siphon is clogged, the water from the sewer can prop back up, or the air will not come out, creating an air traffic jam. In such conditions, the pump is physically unable to pump water. Check if the hose has fallen too low – the hose loop must be fixed at a height of 60-80 cm from the floor to create the necessary hydraulic shutter.
To check the patency of the hose, it is recommended to remove and blow it, as well as visually inspect for the presence of internal deposits. Hard water contributes to the formation of scale, which over time narrows the diameter of the passage. If the hose has become oak or has visible deformations, it is better to replace it with a new one, since rubber products are not subject to restoration.
Use a cable to clean sewer pipes if you suspect a clog at the connection point of the washing machine. Often the problem lies not in the technique, but in the downtrodden knee of the siphon.
Diagnostics and replacement of the drain pump (pump)
When mechanical obstacles are excluded and the hoses are free, the suspect himself is put under suspicion. drain-pump. On the washing machines. Bosch Most often, brand pumps are installed Askoll or Plaset. These devices have limited resources and can fail over time. Signs of malfunction are the absence of rotation of the shaft when applying voltage or strong vibration and noise during operation.
To check the pump, you need to remove the bottom panel of the car (if any) or put the unit on its side (preliminarily covering the floor). The pump is usually attached to the bottom of the tank and has two wires. Call the winding with a multimeter: the resistance of a working engine is usually from 150 to 200 Ohms. If the device shows a break (infinity) or a short circuit (close to zero), the part needs to be replaced.
Replacing the pump is not a complicated procedure, but requires care. The old pump is dismantled, the clamps of the pipes are disconnected. When installing a new one, make sure that the sealing rubber bands sit tightly, and the clamps are tightened reliably. It is also important to check that the garbage from the old pump does not get into the new pipe during installation. After assembly, conduct a test run on the "Plum" mode without underwear.
| Parameter | Normal value. | Sign of malfunction |
|---|---|---|
| Resistance to winding | 150-200 Om | Breakdown or KZ |
| Rotating the impeller | Free, silent. | Snatch, crunch. |
| Condition of the filter | Clean, net intact. | Stuffed with pile, trash. |
| Hose loop height | 60-80 cm | Lying on the floor (syphon effect) |
Problems with wiring and control module
In rare cases, error E21 This may be due to problems with the electrical part not directly connected to the pump motor. Oxidation of contacts in connectors, rubbed wires or voltage surges could damage the control circuit. If the pump is serviceable, but the voltage does not come at the time of activation of the drain, the problem may lie in the control module or the simistor responsible for switching the pump.
Carefully examine the wires running from the module to the pump. Often, rodents or vibrations cause damage to the insulation. Check the pump terminal pad: contacts should be clean, without traces of sodium or oxidation (green or white). If you find oxides, clean them with a contact spray or eraser, but make sure the machine is off-grid.
Diagnostics of the control module requires special knowledge and equipment. If all peripheral elements (hoses, filter, pump, wiring) are serviceable, and the error persists, most likely, the control simistor on the board has failed. In this case, the module in the service center or its complete replacement is required, which is the most expensive option for repair.
Prevention and operation rules
To make a mistake E21 Never appeared on your display again, it is important to follow simple rules of operation. Regular prevention can prolong the life of the drain system for years. The main enemy of the pump is small items in pockets and pile from clothes, so careful preparation of laundry for washing is the first step to a long life of the technique.
Use special bags to wash delicate things. They not only protect the fabric, but also hold off the buttons or bones, preventing them from getting into the drain system. It is also recommended to periodically, at least once every six months, carry out preventive cleaning of the filter, even if the machine is working properly. This will remove the accumulated silt and small particles before they create a plug.
Do not forget about the quality of the washing equipment. The use of powders with low foaming and regular use of scale remedies helps to keep the insides of the machine clean. Excess foam can get into sensors and the pump, causing malfunctions in the electronics and accelerating wear of mechanical parts.
The secret to long-term pump service
Owners who install an additional magnetic filter on the inlet hose of water and use scale tablets, face breakdowns of the pump 3 times less often. Magnets change the structure of salts, preventing them from settling on moving parts.
⚠️ Note: If after cleaning the filter and checking the hoses, the machine continues to give an error, do not try to start the wash cycle repeatedly. This can result in the final failure of the control module or combustion of the pump winding.
When a Master's Challenge is Necessary
Despite the possibility of self-repair, there are situations where you can not do without professional help. If you checked all the available nodes, replaced the pump, but the error E21 It is coming back, so the problem is systemic. Diagnosing complex electronic faults requires an oscilloscope and a deep knowledge of circuit engineering.
It is also worth contacting specialists if the car is under warranty. Self-opening of seals or careless replacement of parts can be the basis for denial of warranty service. A professional master will conduct the diagnosis faster and give a guarantee for the work performed and installed spare parts.
Remember that getting a job done on time can save you a budget in the long run. Attempts to “reanimate” the burned module by folk methods often lead to the fact that repairs become economically inexpedient. Take care of your equipment and trust complex operations to professionals.
90% of E21 errors are solved by simply cleaning the drain filter or replacing a low-cost drain pump, making this repair affordable for self-implementation.
What does it mean to flash indicators instead of error code?
In some models Bosch Without a digital display, the error code is transmitted by a combination of flashing light bulbs. Usually this is a flashing of temperature indicators or spin mode. The number of blinks corresponds to the code number. For the E21, it can be a series of 2 long and 1 short blinking, but the exact transcript is best viewed in the instructions for a particular model.
Can I continue to wash if I have an E21 error?
It's not recommended. The machine won't be able to rinse out the laundry and squeeze it out, leaving things wet and full of detergent. In addition, repeated drain attempts can finally finish the pump or lead to water leaking to the floor.
Why does the pump hum but not pump water?
This is a classic sign of mechanical locking. Most likely, a coin, a bone from a bra or a dense lump of hair / thread got into the impeller. It is also possible to jam the bearing shaft due to corrosion or resource production.
How to Reset E21 Error After Repair
In most cases, it is enough to turn off the machine, wait 10-15 seconds and turn on again. If the error was caused by a temporary failure, it will disappear. If the fault (clogging, breakage) is not eliminated, the error will appear again at the first attempt to drain.