Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
DHW Demand
DHW temperature set to MAX
Attach temperature clamps to flow and return pipes
to secondary heat exchanger
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow appliance to operate for hot water.
Monitor the temperature differential across flow and return pipes.
Expected temperature differential approximately 25°C or less.
Note.
Flow rate no greater than 14.5 litres/min.