| 04 | Generic anomaly of the boiler PCB. | Internal fault of the ignition/modulation PCB 1.015792: the electronics detect inconsistencies and stop the equipment. Verify that the gas valve and its wiring are correct; if everything is OK and 04 persists, replace the PCB. |
| 01 | Lockout due to ignition failure. | The PCB does not trigger the ignition transformer or does not supply the gas/modulation valve. Check the transformer discharge and the presence of 230 VAC at X1 (1-2) during the 8–10 seconds of safety; if voltage is missing or ionisation is correct and 01 persists, the PCB is faulty. |
| 15 | Configuration error. | The PCB automatically recognizes the type of boiler through the identification wiring; if the auto-identification/memory of the PCB fails, it generates 15. Check the recognition wiring; if they are correct, replace the PCB. |
| 31 | Loss of communication with the Remote Command (CAR). | Communication circuit fault in the PCB: after checking polarity and wiring to terminals 40–41 and testing with a valid CAR, if communication remains lost, the PCB is the cause. |
| 20 | Lockout due to parasitic flame. | The flame control circuit on the PCB detects false ionisation current (leakages/moisture) or a fault in the flame control itself. Check the electrode/ground and wiring; if they are OK and 20 persists, replace the PCB. |
| 24 | Keypad/panel anomaly. | If the buttons and the panel are correct, the keyboard input on the PCB is damaged. Check that there are no stuck keys and the wiring; if everything is OK and 24 persists, replace the PCB. |