The GradedAppliance Hub

Neff F21 on a washer dryer

Drum drive fault — the motor is not turning the drum as commanded.

The same code appears on Bosch and Siemens machines — they share the same control platform.

Verdict

Needs an engineer

Mains electrical, gas or sealed-system work

Urgency
Urgent

About 30 min to work through

Typical cost

£85–£260

DIY: £8–£160 in parts

What F21 actually means

The board asked the motor for a specific speed and the feedback it got back did not match. That can mean the drum is physically obstructed, that the motor is worn out, or that the board section driving the motor has failed. This one crosses the line from householder territory into engineer territory fairly quickly.

Before you start

  • Electrical safety: Motor and control-board work involves mains voltages and stored charge. Unplug the machine before removing any panel, and do not run it with panels off.

What causes it, most likely first

  1. Something jammed between drum and tub

    Common

    An underwire, coin or hair grip that has escaped the drum can wedge between the drum and the outer tub and physically stop it turning.

    How to check: With the machine unplugged, turn the drum by hand. It should spin freely for several revolutions. Grating, or a hard stop, means an obstruction.

  2. Worn motor carbon brushes

    Common

    On brushed motors the carbon blocks wear down over years until they no longer make good contact. Typically the machine washes but will not reach spin speed, and often you can smell hot carbon.

    Motor carbon brushes£8–£22 for the partDIY with care

  3. Snapped or slipping drive belt

    Common

    On belt-driven models a perished belt jumps off the pulley. You hear the motor spin up freely while the drum sits still.

    Drive belt£8–£22 for the partDIY with care

  4. Failed tacho coil or motor

    Occasional

    The tacho tells the board how fast the motor is actually going. If it fails, the board sees no rotation regardless of what the motor is doing, and shuts down.

    Drive motor£60–£160 for the partEngineer

  5. Seized drum bearings

    Occasional

    Badly worn bearings load the motor beyond what it can drive. Usually preceded by months of rumbling and a drum with noticeable up-and-down play.

    Drum bearing kit£25–£70 for the partEngineer

  6. Control board motor triac failure

    Occasional

    The board component that switches power to the motor can fail. Diagnosis needs live testing, and the board is the most expensive single part in the machine.

    Main control board (PCB)£70–£220 for the partEngineer

How to fix it, step by step

  1. Unplug the machine and turn the drum by hand

    Open the door and rotate the drum slowly through several full turns in both directions. Free and quiet is good. A hard stop means an obstruction; a deep rumble or grinding points at bearings.

    5 min

  2. Check for a foreign object

    Shine a torch through the drum holes while turning it slowly and look for a glint of wire or metal wedged behind. Also check the pump filter — objects often end up there first.

    10 minTorch

  3. Power-cycle and try a spin-only cycle

    Switch off at the wall for a minute, restore power, and select a spin-only programme with the drum empty. If it spins normally, the fault was load-related — an unbalanced or overloaded drum can trigger it.

    10 min

  4. Book an engineer for brushes, belt or motor

    If the drum turns freely and a bare spin still throws F21, the next steps are motor brushes, belt and tacho — all of which mean removing the back panel and working around mains wiring. Quote the F21 code when you book; it points the engineer straight at the drive system.

    5 min

Need an engineer for this F21?

We list 4 washer dryer repair businesses across the UK, 3 of which are Neff-authorised. Diagnostic callouts typically start around £55, and many will put that towards the repair if you go ahead.

Find washer dryer engineers near you

Parts you might need

Typical UK prices for the part alone, before fitting. Worth knowing before you accept a quote — the part is often a small share of what a repair is priced at.

  • Motor carbon brushes

    Two sacrificial carbon blocks that carry current into a brushed motor. They wear down over years and are a cheap, planned replacement.

    £8–£22

  • Drive belt

    Links the motor pulley to the drum pulley on belt-driven machines. A snapped belt gives you a motor that runs and a drum that does not.

    £8–£22

  • Drum bearing kit

    The bearings the drum spins on, plus the shaft seal. Replacing them is a full strip-down and is often the point at which a repair stops being worth it.

    £25–£70

  • Drive motor

    The motor that turns the drum. On most machines a genuine replacement costs enough to trigger a repair-or-replace decision.

    £60–£160

  • Main control board (PCB)

    The appliance brain. Genuine boards are expensive and often need configuring to the model, so this is rarely a DIY part.

    £70–£220

Worth repairing, or replace it?

At the top of this range the repair costs a significant share of a graded replacement, which typically starts around £280. Worth getting the quote first, then deciding — on a machine under about five years old a repair usually still wins.

Work out if it's worth fixingCompare graded washer dryers

Related problems

Other Neff washer dryers codes

All Neff washer dryers fault codes