Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
Turn Hot Water Tap On
Gain access to PCB (use Insulation Mat as required)
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
If required, reset boiler, press mode and ok for 2 seconds.
Measure for A/C voltage across connector 20 brown & blue leads.
Expected voltage, mains voltage.
Note.
1. PCB connector numbers can be found on the plastic moulding surrounding the board.
2. Ensure a good connection is made or misdiagnosis will occur.
Measure for A/C voltage across connector 20 brown & blue leads.
Expected voltage, mains voltage.
Note.
1. PCB connector numbers can be found on the plastic moulding surrounding the board.
2. Ensure a good connection is made or misdiagnosis will occur.
Isolate as per TOPs P4
and refit as necessary