Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove the connector plugs from the gas valve and unplug
connector ST9 from the right hand side of the PCB.
If available use the Worcester test PCB to assist resistance test
connector ST9 from the right hand side of the PCB.
If available use the Worcester test PCB to assist resistance test
Measurement:
Check gas valve wiring harness for continuity, measure across the two blue (1 & 2)
and purple (3 & 4) leads of PCB connector ST9 to the gas valve connectors.
Check the general lead condition.
and purple (3 & 4) leads of PCB connector ST9 to the gas valve connectors.
Check the general lead condition.
Isolate as per TOPs P4
and refit as necessary