| F.63 | Fault: EEPROM (electronics fault). | Corruption/invalid reading of the EEPROM memory on the PCB; check voltages and connectors on the board and, if it persists after reset, replace the PCB. |
| F.64 | Fault in the electronics / NTC (NTC short circuit or defective electronics). | NTC input or analogue stage of the PCB short-circuited/damaged; check NTC and wiring, and if the sensors are correct, diagnose/replace the PCB. |
| F.65 | Electronic system temperature too high. | Overtemperature detected on the PCB due to external influence or internal defect; check ventilation/location and, if it reappears when cold, replace the PCB. |
| F.67 | Electronic fault/flame: implausible flame signal (defective electronics). | The flame detection circuit on the PCB delivers an invalid signal; rule out electrode/ground and, if the ionisation is correct, the PCB is faulty. |
| F.70 | Invalid appliance code (DSN). | Display and/or PCB were replaced simultaneously without reprogramming the DSN/coding; verify and adjust DSN or coding resistor on the PCB. |
| F.97 | Main PCB self-test failed. | The PCB does not pass its internal self-test due to component/firmware default; repeat start-up and, if it persists, replace the control board. |
| with | No communication between the display and the PCB (communication fault). | The line and interface of the PCB do not communicate with the panel; check the bus/wiring and connectors, and if they are correct, the PCB (or the display) is faulty. |
| F.61 | Gas valve activation/operation error. | Fault in the valve driver/control on the PCB or PCB-valve communication; check the harness and valve coils, and if they are correct, the PCB is damaged. |
| F.62 | Gas valve switch-off delay. | The closing signal from the PCB arrives late/incorrectly or the board's driver fails; if the valve is sealed, the origin is the PCB (signal/power stage). |
| F.26 | Current of the stepper motor gas valve not plausible. | Reading/control stage fault in the PCB towards the stepper motor of the valve; if connections and valve are OK, the fault is in the PCB. |