Set Appliance State:

Mains Power Off
Set Multimeter to AC Voltage Set meter to measure AC Volts
Turn Hot Water Tap On
Gain access to PCB (use Insulation Mat as required)
Selector switch in DHW position
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:


Allow fan to run and ignition sequence to commence.
Test 1:
Measure the voltage across brown wire (marked GV) on connector X5
and neutral (marked N) on connector X1 on PCB.
Test 2:
Repeat test across black wire on connector X5 and neutral (marked N) on connector X1 on PCB.
Note:
Voltage will only be present for approximately 10 seconds, with no burner ignition lockout should occur.
This can be reset by switching the mains power supply to the appliance OFF and ON again.