Set Appliance State:
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Measurement:
Remove the Grey and Brown wires (1) from the Gas Valve Solenoid Coil 2.
Measure the resistance across the two spade terminals on the Solenoid Coil.
The resistance measured should be approximately 4.2 K ohms for SIT valve
and 5.2 K ohms for Honeywell valve.
Note:
It may be necessary to remove the solenoid coil from the SIT valve to take measurement. It is held in position by two securing screws (2).
Measure the resistance across the two spade terminals on the Solenoid Coil.
The resistance measured should be approximately 4.2 K ohms for SIT valve
and 5.2 K ohms for Honeywell valve.
Note:
It may be necessary to remove the solenoid coil from the SIT valve to take measurement. It is held in position by two securing screws (2).
Isolate as per TOPs P4
and refit as necessary