Set Appliance State:

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

Observation:

Does burner remain alight?
NOTE:
If the boiler goes to lockout-reset by switching the On/Off switch to OFF for approximately 10 seconds and then ON again.