| F.61 | Fault: gas valve operation | The PCB cannot actuate the gas valve (coils short-circuited/open or harness damaged), so it does not open/close. Check continuity/insulation of coils and wiring to the valve and ensure the PCB delivers a signal according to the manual. |
| F.62 | Gas valve disconnection delay | The gas valve does not close in time or remains slightly open, and the equipment detects gas/flame after the stop command. Check the valve's tightness and closure (leak test and ionization reading) and the electrical condition of the valve/wiring. |
| F.26 | Stepper motor current of gas valve not plausible | Stepper motor fault of the gas valve (disconnected, faulty, or with interrupted wiring) prevents positioning. Check connectors/harness, coil resistance of the stepper, and signal from the PCB; replace the valve if the motor does not respond. |
| F.27 | Safety shutdown: flame simulation | An internal leak in the gas valve (solenoid that does not close tightly) can allow gas to pass through and the equipment 'sees' a flame without demand. Check the tightness and closure of the solenoid with a leak test/manometer and electrical check of the valve. |
| F.28 | The appliance does not start: unsuccessful ignition attempts | If the gas valve is faulty, improperly adjusted, or not the correct part, it does not supply gas for ignition. Check inlet pressure, valve adjustment/offset, and control from the PCB; confirm with diagnostics that the valve operates and replace/adjust if necessary. |
