Miele Dishwasher F24 / F25: Heating Faults
F24 points at the heater relay circuit; F25 means the wash water never reached its target temperature in time. Different codes, same customer complaint: greasy dishes, cloudy glasses, tablets that don’t fully dissolve.
How the fault develops
The flow-through heater draws serious current, switched by a relay on the power electronics. Years of hard-water scale make the heater work longer per cycle; longer relay on-time cooks the relay contacts. Eventually you get F24 (relay/contact fault detected) or the slower version, F25 (heat commanded, temperature rise too slow or absent — weak element, welded/failing relay, or a scaled temperature sensor lying to the control).
Owner checks — limited but real
- Confirm the machine is on its own dedicated circuit and the breaker/GFCI hasn’t half-tripped; brownouts mimic heating faults.
- Run a hot-tap prime: run the kitchen hot tap before starting a cycle. It doesn’t fix F24/F25, but if “cold dishes” complaints vanish, your issue may be an incoming-water/energy-save setting rather than a hard fault.
- A citric descale cycle (as with F14) occasionally clears a marginal F25 on scaled sensors.
Anything beyond that is live electrical measurement on the power board — not a DIY zone.
The repair
We measure element resistance and insulation, relay behavior under load, and NTC readings against Miele spec. Typical outcomes: relay/power-board repair, heater unit replacement, or sensor replacement. All are one-visit jobs with van stock for G 7000/G 5000 in the Pleasant Hill area.
FAQ
Dishes are wet and cold but no code shows.
Heating can degrade before a hard code logs. Mention it when booking — we’ll check the same circuit.
Is F24 a fire risk?
The machine cuts heating when it detects the fault, that’s the protection working. But a relay failing under load deserves prompt service, not months of ignoring.
Softener salt — does it really matter here?
Yes. A correctly charged internal softener is the cheapest heater-life insurance on CCWD water.
