Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Volts Set meter to measure AC Volts
DHW Demand
Gain access to PCB (use Insulation Mat as required)
Boiler mains switch ON
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Allow the ignition sequence to commence and burner to ignite.
Measure the voltage across the black and blue leads at the diverter valve connector on PCB X6.