Set Appliance State:

Ensure NO demands
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Test 1:
Are any symbols shown on the display?
(if not, press the power button once briefly)
Test 2:
Reset the appliance.
(press and hold the power button for 4 seconds then release)
As the appliance turns on or resets multiple symbols in the display will be shown briefly before the appliance commences its self check.
Does the display illuminate and multiple symbols display briefly?