Set Appliance State:

Mains Power Off
Turn Hot Water Tap On
Heating temperature selector to OFF
Hot water temperature selector to maximum
Ensure heat bank is up to temperature
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

With hot tap fully open and a flow rate of approximately 18 l/min is there a temperature rise of approximately 35 degrees C and is the operation satisfactory with a constant DHW temperature maintained?
Note:
There may be a short delay, approximately 10 seconds, between demand and the burner firing.
The burner will fire as heat bank temperature falls.