Dishwasher displays F3 and stops; water inside is cold and dishes are not cleaned properly.

Safety first: Disconnect mains power and ensure the machine is completely cool before accessing internal components.

• Confirm symptom: Run a short cycle and check if the interior and door are warm after 15–20 minutes. If not, the heater is likely not operating.
• Inspect wiring: Remove the lower kick plate and side panels (if accessible). Look for burned or loose connectors on the heater terminals and NTC sensor harness.
• Check continuity (advanced): Using a multimeter (with power disconnected), measure resistance across the heater terminals on the Fagor circulation pump/heater assembly. An open circuit indicates a failed heater.
• Check NTC sensor: Locate the NTC sensor in the sump or heater housing. Measure its resistance at room temperature and compare with Fagor service specifications; a short or open reading indicates failure.
• Control board: If heater and NTC test good, the main PCB heater relay or triac may be defective. This requires board-level diagnosis or replacement by a professional.