Set Appliance State:

Mains Power Off
Ensure boiler is Cool and no demand for DHW and CH
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset boiler.
Does the boiler reset?
(Reset is confirmed by the display returning to show flow temperature of appliance)
Note.
1. To reset boiler, press and hold the reset button for one second.
2. If the boiler fails to reset and a fault code other than E07 appears CLICK HERE.