F1/F4 - Ignition Fault Boiler failed to light
F2/F3 - Fan Fault
F5 - Overheat Fault
F6 - Central Heating flow thermistor fault
F7 - Domestic Hot Water thermistor fault
F9 - Fault code displayed
F10 - Central Heating return thermistor fault
F11/F13 - Main board connection fault
F8/F12 - User interface connection fault