Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
Turn Hot Water Tap On
Selector switch to DHW position
CH temperature selector to minimum
DHW Preheat selector to OFF position
CH temperature selector to minimum
DHW Preheat selector to OFF position
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Allow fan to run and ignition sequence to commence.
After approximately five seconds, measure the voltage at connection 2 (blue lead) and connection 4 (brown lead) at connector A1 on the PCB.
Voltage will only be present for approximately 10 seconds. As burner will not ignite, boiler may go to lockout.
Note:
The position and orientation of the connectors can differ slightly dependent on the PCB version, however the test remains the same.
After approximately five seconds, measure the voltage at connection 2 (blue lead) and connection 4 (brown lead) at connector A1 on the PCB.
Voltage will only be present for approximately 10 seconds. As burner will not ignite, boiler may go to lockout.
Note:
The position and orientation of the connectors can differ slightly dependent on the PCB version, however the test remains the same.
Isolate as per TOPs P4
and refit as necessary