| F.63 | Fault: EEPROM | The EEPROM memory of the PCB is damaged or unreadable. Check the power supply voltages of the PCB and attempt a reset; if F.63 persists after ruling out power supply and parameterisation, replace the PCB. |
| F.64 | Fault: PCB / sensor / analog to digital transformer | Defect in the A/D converter or sensor reading stage in the PCB. Rule out NTCs and wiring (resistance/continuity measurement); if they are correct and F.64 persists, the cause is the PCB. |
| F.65 | Error: electronics temperature too high | The PCB electronics detect overheating (sensor/measurement on PCB). Check ventilation and thermal conditions; if the F.65 reappears when cold after ruling out external causes, the PCB is defective. |
| F.67 | Incorrect value returned by ASIC (flame signal) | Fault in the detection/ASIC stage of the board that evaluates ionisation. Check electrode, cable, and grounding; if everything is correct and the signal is still not plausible, the fault is in the PCB. |
| F.70 | Invalid product code (DSN) | Main PCB and interface mounted without recoding the DSN/power class resistor or incompatible. Check and recode in service menu (.d.93); if it does not accept coding or reappears, replace/parameterize the correct PCB. |
| F.61 | Error: gas valve control | Fault in the driver/output of the control board that governs the coils of the gas valve. Rule out shorts in the harness and coils; if they are correct and the manual considers 'defective electronics', the PCB is the cause. |