What this error means
Water supply fault — the machine is filling too slowly or the fill timed out
The F12 error means the machine detected water entering but the fill phase took longer than the maximum permitted time before the required level was reached. This is distinct from F10 where no water entered at all. F12 is most commonly caused by a partially closed water tap, a kinked inlet hose, a partially blocked inlet filter mesh, or borderline low supply pressure.
What you'll need first
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Step-by-step
Symptoms to look for
- Machine begins to fill but takes far longer than the display estimate before progressing
- Programme pauses during the fill phase before F12 is displayed
- Fill progress indicator moves very slowly or stops partway
- F12 appears consistently on every hot programme but not on cold washes
How to fix it
Turn the cold water isolation tap fully anti-clockwise. Even a small restriction reduces flow below the Miele minimum fill rate. If uncertain whether the tap moved, close it fully then reopen it fully.
Pull the machine carefully away from the wall. Run your hand along the full hose and straighten every kink or compression. Push the machine back while watching the hose to confirm it does not kink again.
Turn the tap off. Unscrew the hose fitting at the back of the machine. Remove the small mesh filter from inside the inlet port using tweezers. Rinse it under running water and scrub it with an old toothbrush to clear all limescale deposits. Refit firmly.
Disconnect the hose from the machine, point it into a bucket and briefly open the tap. The flow should be strong and uninterrupted. Miele machines require a minimum of 1 bar. A flow that looks reasonable by eye may still be below this threshold.
With the machine completely unplugged and water off, remove the rear panel. Check the inlet valve body for mineral deposits that could be partially restricting the internal channel. A valve that opens slowly or only partially will cause F12 even with a full supply.
Reassemble, restore water supply fully and start a 40-degree programme. Watch the fill status on the Miele display — it should progress steadily without pausing.
When to call an engineer
- Water supply pressure confirmed adequate but F12 persists after filter cleaning — inlet valve partially failing
- Inlet valve solenoid coil reads high resistance or open circuit — valve needs replacing
- F12 appears even with a new inlet valve — supply pressure may be consistently below 1 bar
- Wiring to the inlet valve is corroded or the connector is not fully seated
Frequently asked questions
What is the difference between F10 and F12 on a Miele washing machine?
Why do Miele machines display F12 more readily than other brands?
Can I fix F12 without calling an engineer?
How do I know if the inlet valve needs replacing?
🎯 What is likely causing this fault?
⚠️ Estimates based on common faults — not a guaranteed diagnosis. Always verify before ordering parts.
Parts you may need
Enter your model number to filter results to your exact machine
Usually found on a label inside the door frame or on the back panel of the machine.
| Part | Approx. UK Cost | Find it |
|---|---|---|
| Inlet Valve | £17 - £25 | 🛒 Amazon UK → |
| Inlet Valve | £19 - £25 | 🏷️ eBay UK → |
ℹ️ Prices are approximate. Always check the part number matches your model before ordering. Not sure of your model number? Find out how to locate it here.