Set Appliance State:

Set Multimeter to mVolts DC Set meter to measure DC mVolts
Isolate Mains Power to appliance as per TOPs P4
DHW Demand
DHW Selector in Maximum (+) position
CH Selector in Minimum (-) position
ON/OFF Switch in ON position
Remove the cap on the flame sense electrode
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:


Allow self check to complete and ignition sequence to commence
Measure the voltage across the exposed flame sense electrode terminal and a suitable earth point.
Ensure a flame is present when making the measurement.
As the flame will not be detected the appliance will attempt to relight 5 times.
Expect a flame sense rectification voltage of greater than 30 mV DC.