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:
Measure the AC voltage between the Brown and Blue wires at X18.
Expect a voltage fluctuating between 0 and 240 Vac approximately every 7 seconds.
Note:
If the appliance locks out the voltage will stop fluctuating and the boiler will need to be reset to complete the test.
Expect a voltage fluctuating between 0 and 240 Vac approximately every 7 seconds.
Note:
If the appliance locks out the voltage will stop fluctuating and the boiler will need to be reset to complete the test.
 pcb in situ.gif)
 connector x18.gif)
Isolate as per TOPs P4
and refit as necessary