Set Appliance State:

Mains Power Off
Gas On; Pilot On
Turn Hot Water Tap On
Selector Switch in summer position
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Turn on Hot Water Tap and set flow rate by adjusting water throttle to approximately 2.5 gal/min (11.4 litres/min) OR 1 pint in 3 seconds.
This should give a temperature rise of approximately 30 Degrees C.