Set Appliance State:

Mains Power Off
Turn Hot Water Tap On
On/Off Switch in ON position
Mode Selector Switch to Summer
Water Thermostat to MAX
Gas On
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Does the burner ignite?
NOTE:
Boiler must not be at full operating temperature.