Set Appliance State:

Mains Power Off
Ensure there are NO demands
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset appliance if required.
Allow the boiler to commence self check mode, which can take up to 60 seconds, at the end of self check, the boiler flow temperature will be displayed. (see note).
The fan will run for a short period of time (approx. 5 seconds) and then stop.
Choose an option from below, if a fault code occurs during self check choose that option or mis-diagnosis may occur.
Note.
Self check will occur every time the power is re-instated to the boiler.