Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Boiler DHW setting to MAX
Refit diverter valve motor
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Allow boiler to ignite and run on DHW
With a flow rate at the tap of approximately 9.9 litres/min is there a temperature rise of approximately 40° C and is operation satisfactory?
Note:
Flow rates less than stated above will produce a greater temperature rise.