Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Turn Hot Water Tap On
Selector switch set to CH/DHW position
Boiler DHW thermostat set to MAX
Boiler DHW thermostat set to MAX
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Allow fan to run and ignition sequence to commence.
Measure the DC voltage between pin 4 (grey) & pin 5 (brown) on CN8.
Expected voltage approximately 24 Vdc.
Notes:
1. The appliance will only try to ignite once before going to lockout, reset appliance as required until the test is completed.
2. Ensure test probes make a good electrical connection or misdiagnosis will occur.
Measure the DC voltage between pin 4 (grey) & pin 5 (brown) on CN8.
Expected voltage approximately 24 Vdc.
Notes:
1. The appliance will only try to ignite once before going to lockout, reset appliance as required until the test is completed.
2. Ensure test probes make a good electrical connection or misdiagnosis will occur.
Isolate as per TOPs P4
and refit as necessary