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:
Does the display illuminate?
(if it does not, press the power button once briefly)
Test 2:
Reset the appliance.
(press and hold the power button for 4 seconds then release)
After the appliance has reset the display should be illuminated with no fault code and a steady display of the current system pressure (as shown in the example - normal display)
Is the display as described above?