Set Appliance State:

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

Observation:

Reset the appliance (press and hold power button for 4 seconds then release)
The appliance will then start a 1.5 minute self-check program during which the pump should run for approximately 30 seconds.
While the self-check completes set the appliance DHW and CH thermostats to maximum and ensure the "warmstart" facility is turned OFF (no "C" in display).
For guidance on how to amend the settings on the display then click here.
Monitor the appliance for the full 1.5 minutes before selecting an outcome.
If a fault code is shown at the end of the 1.5 minute self-check click here.