Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect the Molex plug from the gas valve
Measurement:
Test 1:
Measure resistance across terminals 1 and 4 of the gas valve.
Expected resistance approximately 4.4kOhms.
Test 2:
Measure resistance from terminal 1 to earth.
Expected resistance open circuit.
Measure resistance across terminals 1 and 4 of the gas valve.
Expected resistance approximately 4.4kOhms.
Test 2:
Measure resistance from terminal 1 to earth.
Expected resistance open circuit.
Isolate as per TOPs P4
and refit as necessary