Set Appliance State:
Mains Power Off
Set Multimeter to AC Voltage 
Turn Hot Water Tap On
Boiler Operating Switch / Programmer set to WATER only
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage across:
- connection 2 (Blue wire) on connector X7 on main PCB (1); and
- connection L3 (Brown wire) on connector CN2 on the Sequence Control PCB (2).
Note:
On some models sequence control PCB may have only numbered connections in which case connection 5 (Brown Wire) should be used for test.
- connection 2 (Blue wire) on connector X7 on main PCB (1); and
- connection L3 (Brown wire) on connector CN2 on the Sequence Control PCB (2).
Note:
On some models sequence control PCB may have only numbered connections in which case connection 5 (Brown Wire) should be used for test.
Isolate as per TOPs P4
and refit as necessary