Set Appliance State:

Mains Power Off
CH Demand
Boiler ON/OFF switch ON
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow boiler to fire and heat system to a reasonable temperature.
Remove the CH demand.
Re-apply CH demand.
Is there a delay of approximately 2 minutes before the boiler re-fires?