Navien NCB300-28K, Service Manual

Page: 42 / 108

System Details 41
4.7.5 Flame Rod Assembly
Item Description
Function Repeatedly discharges a high voltage spark at the main burner until the gas ignites.
Fault
1. Unable to ignite the gas.
2. Results in multiple unsuccessful ignition attempts.
Symptoms
1. The boiler does not ignite and error code E003 or E004 is displayed.
2. The durability of the igniter reduces.
Error codes E003, E004, E012
Diagnostics Visual inspection: Check wire connections are secure and inspect for wire damage.
Testing/inspection
information
BLACK: 0-10 μA
Ignition gap: 3.5-4.5 mm (1/8”)