| F.26 | Fault: gas valve not functioning. | The stepper motor/actuator of the gas valve (0020075740) is disconnected or faulty, so it does not open/close. Check continuity and resistance of coils, connectors, and presence of control signal by running the test program P.0 according to the manual. |
| F.61 | Fault: defective control/operation of the gas valve. | Coils or actuator of the gas valve (0020075740) in short circuit or faulty wiring harness prevent the PCB from activating it. Check wiring, coil resistance, and control signal at terminals (depending on model 24 V=/5 V=) before replacing the valve. |
| F.62 | Fault: delay in the disconnection/closure of the gas valve. | The gas valve (0020075740) closes late or is not sealed, and the control detects a flame after the stop command. Check the valve's seal, burner dirt, connectors/wiring harness, and, if necessary, replace the valve. |
| F.88 | Error: gas valve (connection/short circuit). | The gas valve (0020075740) is incorrectly connected or short-circuited, and the electronics do not recognise it. Check connectors, harness continuity, and coil resistance; if the fault persists, replace the valve. |