Set Appliance State:

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

Observation:

Reset boiler as necessary.
Does the burner ignite and establish?
If boiler detects ignition then display
should show 6 (operating for DHW).
Note:
Burner can be seen via reflective plate on the top left of appliance.