Set Appliance State:

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

Observation:

Allow the burner to ignite and run with a CH demand for 1 minute.
Remove the CH demand.
Does the pump continue to run for approximately 3 minutes?
Notes.
1. This setting is adjustable in the appliance parameter settings.
If the appliance does not behave as described above, it is advisable to check Parameter 2-3-7
2. The default setting is 3 minutes.

Click here for guidance on how to access / modify the parameters.
Alternatively refer to Adapt for guidance.