Set Appliance State:

Mains Power Off
HW Demand
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Mains reset switch On.
Turn HW Demand OFF while burner is operating and observe flame
through sight glass, the flame should extinguish within 1 second.
If any beads of flames remain this would indicate a passing gas valve.