Set Appliance State:
Gas Off
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
Gain access to PCB (use Insulation Mat as required)
Disconnect plug from spark generator
(Push backwards not downwards, easier if
spark generator is removed from appliance)
Disconnect plug from spark generator
(Push backwards not downwards, easier if
spark generator is removed from appliance)
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
During the 3 minute self check:
1. Measure the voltage between the brown wire at X1 to a suitable earth point.
Mains voltage should be present.
2. Measure the voltage between the black wire at X1 to a suitable earth point.
Voltage should be approximately 13V AC.
Allow boiler to continue its self check. When the fan starts monitor
the voltage between the black wire at X1 to a suitable earth point.
Shortly after the fan starts the voltage should drop from 13V AC to 2V or lower.
Note:
Voltage change should be seen for approximately 5 seconds on each attempt at ignition.
1. Measure the voltage between the brown wire at X1 to a suitable earth point.
Mains voltage should be present.
2. Measure the voltage between the black wire at X1 to a suitable earth point.
Voltage should be approximately 13V AC.
Allow boiler to continue its self check. When the fan starts monitor
the voltage between the black wire at X1 to a suitable earth point.
Shortly after the fan starts the voltage should drop from 13V AC to 2V or lower.
Note:
Voltage change should be seen for approximately 5 seconds on each attempt at ignition.
Isolate as per TOPs P4
and refit as necessary