Set Appliance State:

Mains Power Off
Boiler Thermal Store must NOT be at maximum temperature.
Models with Programmer: Rocker Switch to Continuous.
Models without Programmer: Rocker Switch to ON.
Gas On
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Allow the Boiler to run until the Thermal Store reaches maximum temperature.
Boiler should shut down and the Green Neon will extinguish.