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 brown wire to the blue wire next to it at the disconnected plug.
Resistance should be approximately 4.3k - 5.3kΩ.
Test 2:
Measure the resistance at brown wire at the disconnected plug to a suitable earth point.
Resistance should be greater than 1MΩ (or O.L).
Note:
Two types of gas valve lead may be fitted, refer to the image that corresponds to what is fitted on the appliance you are working on.
Measure the resistance across the brown wire to the blue wire next to it at the disconnected plug.
Resistance should be approximately 4.3k - 5.3kΩ.
Test 2:
Measure the resistance at brown wire at the disconnected plug to a suitable earth point.
Resistance should be greater than 1MΩ (or O.L).
Note:
Two types of gas valve lead may be fitted, refer to the image that corresponds to what is fitted on the appliance you are working on.
Isolate as per TOPs P4
and refit as necessary