Set Appliance State:
Set Multimeter to AC Voltage 
Turn Hot Water Tap On
Isolate Mains Power to appliance as per TOPs P4
Boiler Operating Switch / Programmer set to WATER only
Gain access to PCB (use insulation mat as necessary)
Boiler Operating Switch / Programmer set to WATER only
Gain access to PCB (use insulation mat as necessary)
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage across:
-connection L (Brown wire) at connector CN1 on the sequence control PCB (1); and
-Neutral (Blue wire, connection 2 marked N) on connector X7 on the main PCB (2).
Note:
On some models the sequence control PCB may have only numbered connections in which case connection 1 (Brown wire) should be used for test.
-connection L (Brown wire) at connector CN1 on the sequence control PCB (1); and
-Neutral (Blue wire, connection 2 marked N) on connector X7 on the main PCB (2).
Note:
On some models the sequence control PCB may have only numbered connections in which case connection 1 (Brown wire) should be used for test.
Isolate as per TOPs P4
and refit as necessary