Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect ST9 connector from the right hand side of the PCB.
If available use the Worcester test PCB to assist resistance test
If available use the Worcester test PCB to assist resistance test
Measurement:
Measure resistance across gas valve connections, pins 1,2 (blue) and pins 3,4 (purple) leads on connector ST9.
Note.
Gas valve connection plugs can be fitted in any configuration.
Note.
Gas valve connection plugs can be fitted in any configuration.
Isolate as per TOPs P4
and refit as necessary