Siemens washing machine - error f21 - washer.tomathouse.com

Siemens washing machines have a self-diagnosis system. This means that an error code is displayed on the machine’s screen, after decoding which we understand what the problem is and whether there is a need to call a technician. One of these codes is error f21 in a Siemens washing machine.

What does error f21 mean?

With this signal, the device reports incorrect operation of the management system. When the unit issues an error code like this, the set program is automatically interrupted. This malfunction is due to several reasons:

the drive belt functions unevenly;
for a number of reasons, the belt is not capable of transmitting rotational motion to the drum of the Siemens unit;
there was a short circuit on the triacs;
brush wear;
the tachogenerator failed;
reverse relay malfunction.

There is only one solution - replace the failed element.

How to resolve the error

To make sure that Siemens washing machine displays error f21 due to a malfunction of the tachogenerator or worn brushes, you will have to dismantle the electric motor. The procedure is responsible. It implies the presence of sufficient physical strength, because the washing machine will have to be tilted for ease of operation. The algorithm of actions is as follows:

the device is disconnected from all communication lines - electricity, water and sewerage;
the screws are unscrewed, the top panel is removed to make it easier to work;
the back cover of the case is dismantled;
the drive belt pulls off;
The screws securing the motor of the Siemens washing machine are unscrewed. To do this, it is recommended to use a ratchet wrench;
if you are looking at the washing machine from the front, it must be tilted to the left side;
the grounding chip is disconnected;
the motor is removed from the washing mashine.

Masters recommend performing such work with gloves so as not to injure your hands.

The tachogenerator is checked using a tester. The device should not indicate the presence of a break or low voltage. Here it is fair to note that error code f21 is rarely displayed due to a failure of the tachogenerator, since a Siemens washing machine is famous for its reliability.

Brushes are checked visually. To do this, you need to remove them from the holder, first taking out the bar made of brass material and disconnecting the contacts from it.

Replacement is carried out when the length of the old brushes does not exceed one centimeter.

Grinding in the brushes

First of all, we check the collector lamellas for integrity. If they deflate, we sharpen them, but such a measure is considered temporary. This motor will have to be replaced or a new rotor selected. We remove brush dust from the motor and clean the grooves of the lamellas. New brushes are installed taking into account the inclination towards the rotor.

The grinding is carried out as follows:

Having replaced the brushes, we return the motor to its place and fix it with screws;
connect the grounding and chips with wires;
set the minimum speed, activate spin program;
To be completely sure, we run the named function again;
install the drive belt;
we carry out a complete assembly of the Siemens washing machine;
do not put dirty things in the drum, run a program with a duration of one hour, set low speed, turn on the machine;
after such a check, you can wash, but the first two or three drum loads are carried out at fifty percent of the permitted rate;
only after such checks can the unit be used in full mode - error f21 on the Siemens washing machine will not bother you.

Error f 21 is triggered due to a module malfunction

What to do if you do not understand anything about electronics and are not able to understand the principle of operation of the washing machine? In this case, it is recommended to entrust the repair of the control board to experienced service center technicians.

Installing a new module is a complicated matter. The module can burn out completely due to mixed up chips and contacts. In this case, the repair will be expensive.

How to reset error f21

Eliminating the cause of this error code in the washing machine is only half the job. The second step is to reset. If you ignore this procedure, the machine will not start working.

The problem is that different models have their own methods, for example, let's consider the procedure for the Siemens iq 300 modification:

the knob for selecting programs is moved to the "0" position;
shift one division in the direction opposite to the clock hand;
press the "Start" key and hold it for a few seconds;
move the knob to the neutral position;
wait for some time;
the error code f21 should reset.

It should be noted that it is not always possible to reset on the first try. Sometimes the given algorithm "works" with the "Spin" key.

Conclusion

Now it’s clear how to fix error f21 on Siemens SMA. The main thing in this matter is identify the malfunction in a timely mannerto eliminate it on our own.