Set Appliance State:

Mains Power Off
Gas Off
Rotary Switch in DHW position
Keep Boiler Case Switch depressed
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Fully depress the ignition button on the boiler control panel.
Does sparking occur at the spark electrode after approximately 10 to 15 seconds?
Note:
Two types of push button ignition switch are used on boiler. Type one is positive action (definite click heard as the button is fully depressed) type two is soft action (no click is heard).