Set Appliance State:

Mains Power Off
Selector switch to Hot Water position
DHW temperature control set to MAX
Preheat OFF
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Ensure the start up sequence has completed, the pump and fan have stopped and the boiler is showing 0.
Run the hot tap with a flow rate of 3 l/min.
The display should show "d" and the fan and pump should run.
Does the boiler react as described above?
FAN AND PUMP RUN AS EXPECTED
DISPLAY SHOWS "d" AND FAN RUNS BUT PUMP DOES NOT
DISPLAY SHOWS "0" AND NEITHER THE FAN NOR THE PUMP RUN
A FAULT CODE IS DISPLAYED AFTER RUNNING THE TAP