Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove the electrical connector from the gas valve

Measurement:

Test 1:
Measure the resistance between the two outer pins on the gas valve 1 and 4.
Expect approximately 52 Ohms.
Test 2:
Measure the resistance between pin 4 on the
gas valve and the earth point on the boiler chassis.
Expected resistance greater than 1 MOhm.
(O.L is acceptable because this is greater than 1MOhm).
Are the resistances measured as expected?