Set Appliance State:
Gas Off
Set Multimeter to AC Voltage 
Isolate Mains Power to appliance as per TOPs P4
Boiler mains switch On
Ensure secondary heat exchanger is cool and there is a demand for Preheat - this can be done by running the hot water with the gas turned off
Boiler mains switch On
Ensure secondary heat exchanger is cool and there is a demand for Preheat - this can be done by running the hot water with the gas turned off
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure voltage across brown lead (live) and pink lead (neutral) at PCB side of inline connector.
Isolate as per TOPs P4
and refit as necessary