Set Appliance State:

Mains Power Off
CH Demand
Selector Switch to Hot Water and Heating
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Does boiler react to CH demand? i.e. pumps run, fan starts.
Note:
There is an re-ignition frequency programme built into the appliance. This is to control the time between ignition cycles - when in heating mode the factory setting is 3 mins. This can be overridden by turning the power to the appliance Off and On again, or turning the function selector to the standby position and back to the heating position.