Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC 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:
Reset appliance as necessary.
Allow boiler to complete its self check.
Once the boiler starts its ignition sequence measure the voltage
between pin 1 (green wire) on LV1 and a suitable earth point.
After the burner ignites the measured voltage should change from
approximately 0V DC to -50V DC or greater (e.g. -80V DC).
Allow boiler to complete its self check.
Once the boiler starts its ignition sequence measure the voltage
between pin 1 (green wire) on LV1 and a suitable earth point.
After the burner ignites the measured voltage should change from
approximately 0V DC to -50V DC or greater (e.g. -80V DC).
Isolate as per TOPs P4
and refit as necessary