Set Appliance State:

Mains Power Off
Gas On; Pilot On
Turn Hot Water Tap On
Boiler Operating Switch in HW position
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

With DHW flow rate of approximately 8.5 l/min (1.9 gals/min) is there a temperature rise of approximately 40 degrees C?