Set Appliance State:

Mains Power Off
ON/OFF switch ON (recessed position, pushed in)
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

1. Does the display illuminate?
2. Reset appliance, after reset the boiler will run a self-check, allow 40 seconds for self check to complete before proceeding.
If a fault code, previously unrecorded fault or low system pressure is displayed after self check has completed then choose that option from below, if not choose display illuminated.