Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
DHW Demand
DHW Selector in Maximum (+) position
CH Selector in Minimum (-) position
ON/OFF Switch in ON position
Gain access to PCB (use insulation mat as necessary)
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure the voltage across the 3 blue and 4 brown wires of the pump plug at JP6 on the PCB (do not remove plug).
Expect mains voltage.