SUNFEEL DO4230TIN Manual Del Usuario página 17

If the heater is locked, only can be operated, all other buttons are blocked.
If there is any other button operated in the blocked mode, the buzzer signal
sounds and the Key Lock Indicator flashes as indication for the activated
key lock functionality. Only the switch off by operation of is possible. But
if you switched off the appliance, you can not restart it again without
unlocking.
After pressing 2 sec, the Key Lock Indicator disappears. Now, the hob
control is unlocked and can be operated in normal order.
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