Observation:
Boiler has several options within its internal diagnostics to assist in fault finding.
To access the fault finding:
Ensure appliance is not in self check mode.
    (press reset button to skip if necessary)
Press the " i " button for approx. 10 seconds until display shows 00
Press the DHW +/- buttons to move through options 00 to 10
Press the CH + or - button to enter selected option.
Diagnostic Numbers Correspond to:
00 = Flow Temperature
01 = Return Temperature
02 = DHW Temperature
03 = N/A to boiler
04 = N/A to boiler
05 = ON or OFF is flame detected
06 = Outdoor Sensor Temperature
07 = Current Fan Speed
08 = System Pressure
09 = Flame Current
10 = N/A to boiler
To access the fault finding:
    (press reset button to skip if necessary)
Diagnostic Numbers Correspond to:
00 = Flow Temperature
01 = Return Temperature
02 = DHW Temperature
03 = N/A to boiler
04 = N/A to boiler
05 = ON or OFF is flame detected
06 = Outdoor Sensor Temperature
07 = Current Fan Speed
08 = System Pressure
09 = Flame Current
10 = N/A to boiler