Navien NCB300-28K, Service Manual

Page: 62 / 108

Troubleshooting 61
Error type Cause Testing method
Ignition failure
Ignition gap: 3.5-4.5 mm (1/8”)
No spark from the
electrode
When no discharge is seen at the electrode during ignition:
●
Remove the electrode and check for cracks in the insulator.
●
Adjust the gap if discharge is visible.
●
Ensure that the insulating gasket is fitted between the electrode and burner casing.
●
Check the input voltage at the ignition transformer (AC 230 V).
●
If the voltage is correct, replace the ignition transformer.
●
If there is no or low voltage at the ignition transformer, replace the PCB.
●
Check the insulator boots on the spark leads for cracks or holes.
Ignition transformer