Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect the main multi-pin connector from the gas valve
Measurement:
Test 1:
Measure the resistance between pins 1 - 3 and pins 3 - 4
Expected readings should be approx. as per table below.
Test 2:
Measure the resistance between either pin 1,3 or 4 to the earth (pin 2)
Expected resistance greater than 1 Mohm.
Measure the resistance between pins 1 - 3 and pins 3 - 4
Expected readings should be approx. as per table below.
Test 2:
Measure the resistance between either pin 1,3 or 4 to the earth (pin 2)
Expected resistance greater than 1 Mohm.
Isolate as per TOPs P4
and refit as necessary