Set Appliance State:

Mains Power Off
Turn Hot Water Tap On
DHW temperature selector to high setting
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Boiler On/Off switch On.
Reset lockout if necessary.
Allow fan to run and burner to ignite and establish.
After approximately 3 seconds does the fan speed increase?