Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
CH Demand
Attach a temperature clamp to the flow pipe as indicated by the red arrow
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow the boiler to run in central heating mode.
Monitor the temperature of the boiler as it operates.
It should heat until approximately 80°C (maximum temperature) then shut down or maintain temperature at this level without overheating.
Does the boiler behave as described?