Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to DC Volts Set meter to measure DC Volts
Gain access to PCB (use Insulation Mat as required)
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Reset the automatic filling loop counters and ensure the maximum fill time is set to a value to allow you to time to carry out the test.
Remove a small amount of pressure from the system so it is slightly below the set level in the filling loop parameters
Measure the DC voltage to between the 2 pins at the filling loop connector (pink).
Expect approximately 22 VDC while the PCB supplies voltage to the solenoid.
Is the voltage measured as expected?
Note:
The time voltage will be present for will vary based on how much the pressure was reduced, the system size and the mains water supply pressure so the test may need to be repeated to ascertain if the voltage is being supplied.