Observation:

This is a short list of the main diagnostic codes that will be used during fault finding, there are many other codes available to give other information.
To see details of these go to section 13 of the manufacturer’s instructions.
DISPLAYDESCRIPTION
d.0Heating Part Load (in KW, default max. output)
d.1Pump Overrun time (2-60min, default 5min)
d.8External Controls Status (1 = call, 0 = no call)
d.10Pump Status (1,2 = on, 0 = off)
d.34Current Fan Speed (in RPM/10)
d.40Current Flow Temperature
d.41Current Return Temperature
d.44Ionisation Current (>80 no flame, <40 good flame)
d.76Appliance Variant (DSN)
d.99Boiler Status Code (click CONTINUE below for more information)