Set Appliance State:

Mains Power Off
Gas On; Pilot On
CH Demand
Selector switch in CH TIMED position
Ensure clock is set to an ON period
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Does the burner ignite under timed demand?
Note: If power has been switched off or CH demand has been interrupted, there will be a delay of between 1 and 3 minutes before the boiler starts.