Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Selector switch to Hot Water
Gain access to PCB (use insulation mat as necessary)
Gain access to PCB (use insulation mat as necessary)
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Test 1:
Measure voltage between connection 3 (white wire) on connector marked X400 and Earth.
Expect approximately 7 volts DC.
Test 2:
Run DHW tap at 3 litres per minute.
Measure voltage between connection 3 (white wire) on connector marked X400 and Earth again.
The voltage measured should drop to 0 (zero) volts DC.
Do the voltages behave as described?
Measure voltage between connection 3 (white wire) on connector marked X400 and Earth.
Expect approximately 7 volts DC.
Test 2:
Run DHW tap at 3 litres per minute.
Measure voltage between connection 3 (white wire) on connector marked X400 and Earth again.
The voltage measured should drop to 0 (zero) volts DC.
Do the voltages behave as described?
