In short
When a Bosch WAT machine does nothing, start at the socket and the door rather than at the control board. Those two account for most of these calls and they cost nothing to check.
What you observe
- A delay-start time is counting down — The machine is doing exactly what it was asked. It is worth checking before anything is opened.
- The drum hums but does not turn — Power is reaching the motor and something is stopping the drum, so this is a jam or a motor fault rather than a no-start.
- It starts only after being switched off and on — A control that needs a power cycle to accept a start is a real fault, but an intermittent one rather than a dead machine.
- The machine beeps when start is pressed and then stops — An input was accepted and a check failed straight afterwards, which usually means a lock or a level condition.
- A padlock or key symbol is showing — Child lock is engaged. It is designed to be non-obvious and it stops every input until it is cleared.
Likeliest causes first
- Child lock or delay start engaged — Ranks high because it produces an apparently dead machine with nothing wrong, and because it is easy to set by accident.
- No supply at the socket — Second and free to test: a tripped breaker, a failed socket or a plug that has worked loose behind the machine.
- Water not arriving so the first gate never passes — The machine accepts the start, waits for its fill, and appears to be doing nothing at all. Closed taps are the usual reason.
- Programme not actually started — On machines with a separate selection and start step it is common to leave a cycle selected and never started, especially after a power interruption.
What to check first, second, third
- Switch off at the wall for a minute and try again — Clears a control that has hung after a power interruption, and a machine that then runs has told you the fault was transient.
- Test the socket with a lamp or another appliance — It separates the dead-machine branch from the waiting-machine branch instantly, and it needs nothing you do not already own.
- Press the door firmly until it latches and listen for the lock — Second because the lock is the first gate the machine checks, and because a soft close is the commonest cause of all.
- Listen for the lock click with the door held closed — A lock that never clicks with a properly closed door has earned suspicion; one that clicks moves the diagnosis downstream.
Power down first
Safety
Disconnect power and close the inlet taps before starting. A machine that has stopped mid-cycle may still be holding a tub full of water, and that water leaves through the drain filter whether you are ready for it or not.
Models in the WAT family
Reference| Model number | Family key |
|---|---|
| WAT28400UC | bosch:washer:wat |
| WAT28401UC | bosch:washer:wat |
| WAT28402UC | bosch:washer:wat |
Where the owner fix ends
Stop and call if the machine has already been part-dismantled and will not go back to a known state. A half-assembled drum machine is the one situation where a service call actually gets cheaper by being made earlier.
Related faults on these models
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