Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Voltage Set meter to measure AC Volts
CH Demand
Selector switch to CH
Remove bottom facia panel
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure the voltage at the two test points above the pump live and the pump neutral (blue and brown wires) at connector ST15 (two pin connector) in the centre of the exposed PCB.