| F.42 | Resistance fault coding (probably in combination with F.70) | The PCB can cause F.42 if the coding resistor (gas type/power) integrated in the PCB fails or if, after replacing the PCB, the DSN has not been reprogrammed; verify by measuring the resistance on the PCB and adjusting the product code (e.g., d.93). |
| F.70 | Invalid product code (DSN) | This appears when both the display and PCB are replaced simultaneously and the DSN is not reconfigured, or if the coding resistor on the PCB is incorrect; check the DSN reading and the coding resistor on the board, and reprogram according to the manual. |
| F.97 | Main PCB self-check fault | The internal self-test of the main PCB fails due to an electronic fault in the board; check power supply and connectors, and if it persists, replace the PCB. |
| F.64 | Electronic fault / NTC | A short circuit/plausibility in NTC can be correct, but if the sensors and wiring are OK, the origin is the electronics of the PCB (analogue inputs/reference); check NTCs and, if they are within range, check/replace the PCB. |
| F.27 | Safety shutdown: incorrect flame detection | The flame control electronics on the PCB can detect spurious flame due to moisture/leakage or a fault in the ionisation circuit on the board; check the electrode, grounding, and if they are correct, verify the detection stage on the PCB. |
| F.62 | Fault: gas valve control / delayed disconnection | The valve driver/relay on the PCB may not cut off in time or may stick, causing a delay in closing; check voltage/timings on the valve and, if the valve assembly is correct, the cause is the electronics of the PCB. |
| F.61 | Error: gas valve control | The PCB can cause F.61 due to a fault in the control circuit of the gas valve (driver/relay); check the wiring and coils of the valve, and if they are correct, replace the PCB. |
