Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect flame sense lead from electrode
Disconnect connecter ST9 from the PCB
If available use the Worcester test PCB
Disconnect connecter ST9 from the PCB
If available use the Worcester test PCB
Measurement:
Measure resistance of the flame sense lead from the electrode connector to pin 8 (green wire) on connector ST9.
Expect continuity / zero resistance.
Visually inspect the condition of the leads insulation for good general condition.
Check the connectors at each end of the harness are in good overall condition and are able to fit securely to the PCB and detection electrode.
Expect continuity / zero resistance.
Visually inspect the condition of the leads insulation for good general condition.
Check the connectors at each end of the harness are in good overall condition and are able to fit securely to the PCB and detection electrode.
Isolate as per TOPs P4
and refit as necessary