Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Measurement:
Remove the blue spaded wire and the white spaded wire from the main solenoid on the gas valve and measure the resistance across the solenoid.
The resistance across the solenoid should be approximately 2.1 kOhms.
The resistance across the solenoid should be approximately 2.1 kOhms.
Isolate as per TOPs P4
and refit as necessary