Set Appliance State:
Gas Off
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
Turn Hot Water Tap On
Gain access to PCB (use Insulation Mat as required)
DHW temperature selector to maximum
DHW temperature selector to maximum
| 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:
Test 1: Measure the voltage between connection 4 (Blue wire) and connection 3 (Brown wire) of PCB connector A1.
Test 2: Measure the voltage between connection 4 (Blue wire) and connection 2 (Black wire) of PCB connector A1.
Voltage will only be present for approximately 10 seconds.
As burner will not ignite, boiler may go to lockout.
Reset appliance and retest as necessary.
After approximately five seconds:
Test 1: Measure the voltage between connection 4 (Blue wire) and connection 3 (Brown wire) of PCB connector A1.
Test 2: Measure the voltage between connection 4 (Blue wire) and connection 2 (Black wire) of PCB connector A1.
Voltage will only be present for approximately 10 seconds.
As burner will not ignite, boiler may go to lockout.
Reset appliance and retest as necessary.
Isolate as per TOPs P4
and refit as necessary