Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to DC Volts Set meter to measure DC Volts
Turn hot water tap on with a flow rate of approximately 3 l/min
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure voltage across the white and black contacts of the flow turbine inline connector.
Voltages should be measured as in the range below.
Connections
Volts DC
white & black
2.0-3.0

Note:
Ensure good connections are made whilst carrying out this test.