Set Appliance State:

Mains Power Off
CH Demand
Selector switch to DHW and CH position
CH temperature selector to maximum
DHW temperature selector to minimum
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow system to heat to approximately 60 degrees C.
Restricting or turning off some radiators on the system will reduce the time taken to reach temperature.
Turn CH temperature selector to minimum - burner should go out.
Turn CH temp selector to maximum.
Is there a delay of approximately 1-3 minutes before burner re-ignites?