Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Volts Set meter to measure AC Volts
CH Demand
Main On/Off Control in the On position
CH Temperature Control to Maximum
Remove side cover from Pump
Remove Yellow plug X12 from Motherboard and make safe
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

If a fault code is displayed press boiler 'Reset' button.
Measure Mains Voltage across L and N of Pump.