Set Appliance State:

WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Set the boiler into service mode:
Turn both DHW and CH temperature control knobs to minimum.
In one continuous movement, turn the DHW control knob approximately 90° clockwise then back to minimum, back 90° clockwise then finally back to minimum again.
After a few seconds the boiler will confirm service mode is activated by making the display alternate between "SF" and the flow temperature.
Does the fan run when the boiler is in service mode?
Note:
If boiler will not enter service mode repeat test several times before selecting that option below as it can be difficult to activate.