Miele Refrigerator F7 / F8: Defrost Heater & Evaporator Fan Faults

F7 is a defrost circuit fault; F8 is an evaporator fan fault. Different components — same ending. Both let frost take over the evaporator coil: the freezer compartment holds temperature while the refrigerator section slowly warms, because the choked coil can’t move enough cold air. On Miele’s dual-evaporator NoFrost architecture the fault is usually confined to one column or circuit, which is why half the unit seems fine.

What’s actually behind it

What we find on service calls, roughly in frequency order:

1. A burnt defrost heater element (F7) — the circuit reads open, defrost cycles stop happening, and frost accumulates for 1–3 weeks before symptoms show.
2. A failed defrost terminator or thermal limiter (F7) — a small, cheap part that aborts every defrost cycle early.
3. A worn evaporator fan motor (F8) — bearings go, speed drops, airflow over the coil collapses.
4. A fan physically iced solid (F8) — the motor is fine but can’t spin; usually secondary to a defrost problem or a door gasket leak feeding moisture.
5. The control board relay that powers the heater or fan — checked last, replaced least.

Can you do anything yourself?

One genuinely useful thing: a full manual defrost. Empty the unit, unplug it, doors open, towels down, 24–48 hours. If the fridge then works normally for a couple of weeks before warming again, you’ve confirmed the frost path — and bought time to schedule service without panic. Do not chip at ice with tools: one punctured evaporator turns a heater-element job into a sealed-system job.

Also check the door gaskets with a dollar bill — if it slides out with no resistance, a leaking gasket may be feeding the frost and the part replacement alone won’t hold. When we diagnose, heater resistance, fan windings and the defrost terminator are all measured against Miele spec; we don’t replace boards on suspicion. Most F7/F8 repairs are completed in a single visit with genuine Miele OEM parts — see our Miele refrigerator repair page.

FAQ

Freezer is cold but the fridge is warm — F7 or F8?

That’s the textbook presentation of both, yes — a frost-choked evaporator or a dead fan starves the fridge section while the freezer coasts. Whether it’s the heater, the fan or the terminator is a 20-minute measurement job, not a guess.

I defrosted it and the code came back.

Expected — the manual defrost removes the ice, not the failed heater or fan that caused it. If the code returned, the part needs replacing; a second manual defrost just resets the clock.

Water on the floor with F7 — related?

Often, yes: when frost finally melts off an overloaded evaporator, it can overwhelm the defrost drain. On panel-ready built-ins that water hides under the unit — worth mentioning when you call.

Related codes: F2 compressor overheat, F3 sensor fault, F21/F22 ice maker faults — or the full Miele fault-code index. Call (650) 658-8508.