| F.26 | Fault: gas valve not functioning. | The stepper motor/actuator of the valve is not connected or the valve assembly is faulty, so it does not open/close. Check by measuring the signal to the modulator, continuity/insulation of coils, and power supply from the PCB. |
| F.61 | Fault: control/activation of the gas valve. | Short circuit to ground in the harness towards the valve or coils in short prevent its activation. Check coil resistance, leaks to ground, and continuity/wiring between the PCB and valve. |
| F.62 | Gas valve fault: disconnection delay/not sealed. | The valve does not close in time or does not seal (leaks), leaving gas when it should not. Check tightness and closing times; soap/manometer test and control signal without the presence of a flame. |
| F.27 | Safety shutdown: incorrect flame detection (flame simulation). | The sealed gas solenoid valve allows gas to pass when it shouldn't, simulating a flame. Verify with a tightness test and ensure there is no opening signal with ionization reading present. |
| F.28 | Start-up fault: ignition failed. | Incorrect/faulty or improperly regulated gas valve prevents gas supply to the burner. Check pressure before/after the valve, correct type, and signal/modulation; adjust or replace the valve. |
| F1 | Ignition fault (lockout). | In Semia/Semia Tek ranges, the gas valve that does not open or is improperly adjusted prevents ignition. Check the supply and ensure the valve opens (manometer on test point, voltage/signal to the actuator) and adjust/replace. |