Set Appliance State:

Mains Power Off
Turn Hot Water Tap On
DHW temperature set to MAX
Boiler ON/OFF switch ON
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Allow boiler to ignite and run.
With a flow rate at the tap of 12 l/min is there a temperature rise of approximately 40 degrees C?
Note:
Flow rates less than that stated above will produce a greater temperature rise.