Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect gas valve plug from PCB (rightmost plug)
Measurement:
Test 1:
Measure the resistance across the black wire to
the blue wire next to it at the disconnected plug.
Resistance should be approximately 1.5kΩ.
Test 2:
Measure the resistance at black wire at the
disconnected plug to a suitable earth point.
Resistance should be greater than 1MΩ (or O.L).
Measure the resistance across the black wire to
the blue wire next to it at the disconnected plug.
Resistance should be approximately 1.5kΩ.
Test 2:
Measure the resistance at black wire at the
disconnected plug to a suitable earth point.
Resistance should be greater than 1MΩ (or O.L).
Isolate as per TOPs P4
and refit as necessary