Set Appliance State:

Mode selector switch to Off/Reset position
CH Demand
Isolate Mains Power to appliance as per TOPs P4
Central heating temperature control set to maximum
Attach temperature clamps to primary flow as indicated
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Mode selector switch to CH position.
Allow fan to run and burner ignite.
Does the boiler run up to temperature (approximately 82°C) then either
maintain temperature or shut down without overheat reoccurring?
Note:
You may wish to turn off some radiators to reduce the time taken for this test.