Set Appliance State:

Mains Power Off
CH and DHW temperature controls set to MAX
ON/OFF switch set to ON position (pushed in)
Ensure NO demands
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset boiler, wait 10 seconds after power is reinstated, press and hold reset button for 5 seconds, then release.
Ensure DHW preheat is switched OFF (ECO MODE), an illuminated ECO button signifies this mode.
Allow the boiler to complete its self-check, this will take approximately 60 seconds, the boiler flow temperature should be displayed during this period.
If no display, fault code or other symbol is encountered then choose that option from below.
Note.
1. During self-check the pump will run and/or pulse for approximately 60 seconds then stop.
2. If a fault code or other symbol is displayed it may not be possible to check / switch off preheat function.
3. Some fault codes will only occur with a demand.