Set Appliance State:
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Disconnect plug connector (marked ST16) from PCB
Disconnect plug connector (marked ST16) from PCB
Measurement:
Check resistance across connections 7 & 8 (brown wires) and connections 9 & 10 (violet wires).
Resistance should be approximately 70 ohms on both tests.
Note:
Care should be taken that probe tips do not touch each other when taking measurement as a false reading will be given. Also ensure that other end of the brown and violet leads are connected to the main gas valve.
Resistance should be approximately 70 ohms on both tests.
Note:
Care should be taken that probe tips do not touch each other when taking measurement as a false reading will be given. Also ensure that other end of the brown and violet leads are connected to the main gas valve.
Isolate as per TOPs P4
and refit as necessary