Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
DHW Demand
Gain access to connector X4 on PCB
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Test for voltage between the second white wire (4) on connector X4 and the blue wire (neutral) on connector X1.
This is to test the PCB is sending voltage up to the pressure switch and should be there on a demand.
The pressure switch doesn't need to be made for the voltage to be present.
Expected Voltage is 30 VDC.
This is to test the PCB is sending voltage up to the pressure switch and should be there on a demand.
The pressure switch doesn't need to be made for the voltage to be present.
Expected Voltage is 30 VDC.
Isolate as per TOPs P4
and refit as necessary