Set Appliance State:
Set Multimeter to DC Volts 
CH Demand
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the DC voltage between pin 1 and pin 12 on the ignition control box.
Expect approximately 0 vdc.
Is the voltage measured as expected?
Expect approximately 0 vdc.
Is the voltage measured as expected?
Isolate as per TOPs P4
and refit as necessary