Set Appliance State:
Mains Power Off
Set Multimeter to DC Volts 
Turn Hot Water Tap On
Set soft light potentiometer to its MID position
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Reset appliance if required (press reset button for 2 seconds and release).
Allow boiler to commence its ignition sequence.
Measure for DC voltage across the gas valve modulation coil.
Approximately 5 seconds after the fan has started 8 - 12 Vdc
should be present for 7 seconds?
Note.
1. Voltage measured could be either negative or positive.
2. Appliance may enter lockout during this test, reset
as required until test is complete.
Allow boiler to commence its ignition sequence.
Measure for DC voltage across the gas valve modulation coil.
Approximately 5 seconds after the fan has started 8 - 12 Vdc
should be present for 7 seconds?
Note.
1. Voltage measured could be either negative or positive.
2. Appliance may enter lockout during this test, reset
as required until test is complete.
Isolate as per TOPs P4
and refit as necessary