Set Appliance State:

Set Multimeter to AC Volts Set meter to measure AC Volts
CH Demand
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Note:
The pump is not an integral part of the boiler it will be located elsewhere on the system.
Remove the connection cover from the pump and with the external controls calling for heat check for voltage across the terminals marked L and N of the pump.
Expect mains voltage.