| F.61 | Gas valve activation error | The driver/relay of the PCB does not activate the gas valve when there is a demand. Check the voltage at the terminals of the valve during the request; if the wiring and valve are correct and no stable command is received, the PCB is defective. |
| F.62 | Gas valve disconnection delay | The output from the PCB to the valve remains stuck or leaking (relay/power stage), keeping the valve energized after shutdown. Check that the voltage to the valve drops immediately when the flame ceases; if the voltage persists and the valve closes when manually de-energized, the PCB is the cause. |
| F.63 | Fault: EEPROM | Corruption/invalid reading of the EEPROM memory in the PCB. Check retry and power supply stability; if the fault persists, reprogram if applicable or replace the PCB. |
| F.64 | Electronic fault / NTC | Fault in the measurement circuit on the PCB interpreting a short circuit in the NTC even when correct. Check NTC resistances in the sensor and in the board connector; if readings are correct and the warning persists, the fault is in the analog input of the PCB. |
| F.65 | Fault: PCB temperature | The PCB detects internal overtemperature or its thermal sensor is damaged. Check for external thermal influence and ventilation; if the ambient temperature is normal and the issue persists, the electronics/PCB is faulty. |
| F.67 | Fault: electronics/flame | Fault in the flame evaluation electronics of the PCB (implausible ionization signal). Check electrode/cable and ionization current; if they are correct and still implausible, the detection stage in the PCB is faulty. |
| F.70 | Invalid appliance code (DSN) | Display and PCB have been replaced without reprogramming the DSN/coding, or the power coding of the board does not match. Check/adjust DSN in service menu and coding resistor; if not possible, install the correct PCB and parameterize. |
