What this error means
Flood protection activated — the Miele Waterproof System has detected water in the machine base
The F51 error is the primary Waterproof System flood protection code on Miele dishwashers. It means the float sensor in the base tray has been triggered by water accumulation. F51 and F11 both relate to the Miele Waterproof System but may be triggered by different parts of the system depending on the Miele dishwasher model. F51 typically indicates the base tray float sensor has been triggered by a leak from any internal source — a door seal, an internal hose, a pump seal, or the tub itself.
Step-by-step
Symptoms to look for
- F51 displayed during any phase of the programme
- Water visible on the floor directly under the Miele dishwasher
- Machine starts then immediately activates drain pump and displays F51
- Recurring F51 after drying — either the leak source has not been repaired or the float sensor is stuck
What to check
Unplug the machine and turn the water supply tap off at the wall — both steps are essential.
Remove the lower kickplate panel carefully. Shine a torch into the machine base and systematically check every potential leak point — the full circumference of the door seal, the circulation pump shaft seal, both ends of the inlet hose inside the machine, the sump-to-pump hose connections, and the drain hose connection at the pump. On Miele dishwashers particular attention should be paid to the circulation pump shaft seal and the door seal lower corners as these are the most common F51 leak sources.
Open the door and run your fingers around the complete circumference of the Miele door seal, pressing into the full depth of the seal profile. Check for any cracking, tearing, or areas where the seal has detached from its retaining channel.
If the machine is fitted with a Waterproof inlet hose, examine the outer plastic sleeve along its full length for bulging, dampness, or swelling.
With the kickplate removed and the machine unplugged, inspect all hose connections in the base. Miele uses a combination of spring clips and screw clamps. Check that every clip is in position and fully engaged, and that all hoses are seated fully onto their stub connectors.
Once the source has been found and repaired, dry the base tray completely using dry cloths and sponge, then allow 2 to 3 hours to air dry with the kickplate removed. The Miele Waterproof float sensor is highly sensitive — even a small amount of residual moisture will keep it in the raised position and F51 will return on the next cycle.
Restore power and water and run a Quick Intensive programme while remaining present throughout. After 5 minutes and again at the end of the cycle, check the base tray through the kickplate opening for any sign of new water.
When to call an engineer
- Door seal is cracked, torn, or has come away from its retaining channel — genuine Miele replacement required
- Waterproof inlet hose outer sleeve is wet or swollen — complete genuine Miele Waterproof hose replacement required
- Circulation pump shaft seal is weeping — Miele service required for pump seal replacement
- Miele Waterproof float sensor remains raised after base tray confirmed completely dry — sensor needs replacing
Frequently asked questions
Is F51 dangerous on a Miele dishwasher?
What is the difference between F11 and F51 on a Miele dishwasher?
Can the Miele Waterproof sensor be stuck in the raised position?
How do I know the base tray is dry enough to restart safely?
🎯 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 |
|---|---|---|
| Float switch | £20 - £30 | 🏷️ 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.