F3

Miele Overheat Protection / Safety Thermostat Trip

Display shows F3; machine may overheat or not reach correct temperature

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Tripped thermal fuse or safety thermostat on heater block, scaled heater causing localized overheating, blocked water flow through thermoblock, defective heater relay on control board

How to Fix / Troubleshooting

Safety first: Unplug the machine and allow it to cool completely (at least 30 minutes) before opening.

Initial steps:

Descale the machine using Miele-approved descaling tablets and the built-in descaling program to restore proper water flow.
Ensure the water tank is filled and properly seated; low or interrupted flow can cause overheating.

Inspection:

Remove covers to access the heater block/thermoblock.
Locate the safety thermostat or thermal fuse mounted on or near the heater. Check for a manual reset button (some thermostats have a small red or black button).
If present, press the reset button firmly. If it clicks, it was tripped. Reassemble and test.
If a one-shot thermal fuse is present, test continuity with a multimeter. An open fuse must be replaced.

Further checks:

Inspect for heavy limescale buildup on the heater and internal tubing; severe scaling may require professional descaling or heater replacement.
If the thermostat/fuse trips again quickly, there may be a control board or heater fault. Do not bypass safety devices; contact a technician.

Repair Difficulty

Hard 4/5

Required Part

Heater Block Safety Thermostat / Thermal Fuse

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