Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
Gain access to PCB (use Insulation Mat as required)
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Locate connector X10, top left corner of the PCB.
Ensure boilers Isolation switch is turned on and measure the voltage across Pin-1 (Brown) and Pin-2 (Blue).
Expect mains voltage at the connector.
Ensure boilers Isolation switch is turned on and measure the voltage across Pin-1 (Brown) and Pin-2 (Blue).
Expect mains voltage at the connector.
Isolate as per TOPs P4
and refit as necessary