Hansa oven displays E05 and the cooling fan runs continuously or not at all; oven may shut down during use.

Safety first: Disconnect power and allow the oven to cool completely before accessing internal components.

• Check fan operation: With the oven reconnected and set to a heating mode, listen for the cooling fan (not the convection fan) starting at the top or rear of the unit. If it does not run or is very noisy, suspect a fan issue.
• Inspect for obstructions: Remove the top cover to access the cooling fan. Look for insulation, wiring, or debris obstructing the blades. Clear any blockage and ensure the fan spins freely by hand.
• Test the fan motor: Disconnect the fan and measure its resistance. An open circuit indicates a failed motor. You can also apply mains voltage carefully (only if qualified) to confirm operation.
• Check overheat thermostat: Locate the chassis overheat thermostat (usually a small round device clipped to the top or rear). Test for continuity at room temperature. If open, replace it.
• Control board output: If the fan and thermostat are good but E05 persists, the control board's fan driver (relay or triac) may be faulty and require board replacement.

When to call a technician: If you are not comfortable removing the oven from cabinetry or working near mains wiring, have a professional handle fan and thermostat diagnostics.