Set Appliance State:

Mains Power Off
CH Demand
Selector Switch in Heating & Hot Water Position
CH temperature set to Max
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow burner to ignite and to run for a short period so it begins to warm the system.
Turn CH demand OFF.
Does the pump continue for approximately 1 minute after demand has been removed?