The F21 code on the display is most often accompanied by a stop of the washing machine during the execution of the program or at its very start. The error signals a problem with the drum - most likely it does not rotate at all or stops earlier than the planned time. On models without a display, in this case three indicators light up: a rinse lamp, the maximum number of revolutions (this is 1000 or 800), and also one after it (800 or 600):
Before you see the code or its analogue, the machine may try several times to independently solve the problem: re-launch the drum. If a series of attempts fail, the program will stop and signal a malfunction.
Also read: How to fix error F16 in the Bosch washing machine?
What to do on your own?
- Drain, remove the laundry and carefully examine everything inside. Check that there is no laundry or debris blocking the normal course of rotation between the drum and the tank. Easily scroll it by hand and listen - foreign parts will give themselves an unpleasant creak;
- Make sure that the mains voltage is normal. Unfortunately, this is a common problem with private homes.
What needs to be repaired?
Independent verification did not give positive results? Then you should contact the master. You may need to replace one of the following parts:
- Sensor monitoring the speed of the drum;
- Motor - the whole or individual parts, for example, brushes.