Set Appliance State:

Mains Power Off
Boiler mains switch ON
Set CH temperature to MAX
CH demand
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow boiler to ignite and heat the CH system to heat.
As the temperature of the system nears 82°C does the fan speed reduce as the temperature demand is met?
Note:
To reduce the time taken for this test some radiators can be temporarily turned off to reduce heat up time.