Set Appliance State:

Mains Power Off
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 to approximately 2.5 gal/min (11.4 litres/min) OR 1 pint in 3 seconds at water throttle.
This should give a temperature rise of approximately 30°C.