Set Appliance State:

CH Demand
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow appliance to fire and system to heat.
Does the appliance reach approx 82 - 85°C then either maintain temperature or shut down without faulting?
Note:
To reduce the time taken for this test you may wish to turn off some radiators.