Set Appliance State:

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

Observation:

ON OFF switch ON
After power reinstated to boiler the display will be blank for approx 10 seconds.
Then the display should come on with the boiler temperature and ECO may also be shown.
There may also be a fault code in the display.
CLICK HERE IF FAULT CODE SHOWN