Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Selector Switch to Hot Water and Heating
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:
Measure voltage across connection 7 (white wire) on connector marked X400 and Earth.
Expect approximately 7 volts DC.
Turn DHW tap on.
Measure voltage across connection 7 (white wire) on connector marked X400 and Earth.
Expected voltage volts should drop to 0 (zero) volts DC.
Expect approximately 7 volts DC.
Turn DHW tap on.
Measure voltage across connection 7 (white wire) on connector marked X400 and Earth.
Expected voltage volts should drop to 0 (zero) volts DC.
