F0 checks
| Step | Check | If yes | If no / next |
|---|---|---|---|
| 1 | Reset button flashing? | Reset for 3 seconds. Raise heat demand with the boost button, cancel after 30 seconds, and repeat twice. If F0 remains, go to step 2. | Go to step 2. |
| 2 | PCB damaged | Note service settings, replace the PCB, restore settings. |
Gas work stays with a Gas Safe registered engineer. These steps are guidance from the manufacturer sequence, not a substitute for the handbook.