F20 error on induction cooktop; one or more zones do not heat.

Safety first: Turn off the cooktop at the breaker and allow it to cool completely before removing it from the countertop.

• Allow cooling: If F20 appears after heavy use, let the cooktop cool for 30–60 minutes and try again. Ensure ventilation slots are not blocked.
• Check ventilation: Verify that there is adequate clearance under the cooktop per Blomberg installation instructions and that fans are not obstructed by insulation or cabinetry.
• Inspect internal fans: Remove the cooktop from the counter and the bottom cover. Check that the cooling fan runs freely and is not clogged with dust. Replace if seized or noisy.
• Check coil sensor wiring: Each induction coil has a temperature sensor. Inspect wiring and connectors for damage or loose fit.
• Replace sensor or power module: If a specific zone always triggers F20, the sensor or that zone's power module may be defective and should be replaced.