Navien NCB500-2S/37K Service Manual page 63

5.2.2 Error 003
Error Conditions and Checklist
Error
E003
Ignition fault
Checklist
Scenario1
Is the igniter
operating correctly?
Yes
Check the gas valve assembly
62 Troubleshooting
When ignition faults occur, the boiler will attempt ignition 5 times. If a flame does not
start, the system displays E003 on the front panel. This error code can be cleared manually.
1. Check the gas supply valve is open and use a manometer to verify the supply pressure
is correct.
2. Check the ignition gap, spark intensity, and flame rod deformation.
3. Check the operation of the ignition transformer (ignition state, input power (AC 230 V)
4. Check the operation of the gas control valve (DC 24 V, coil short circuit, solenoid
valve).
5. Check the flame rod, wiring, and grounding.
6. Check if the air pressure hose is broken or obstructed.
7. Check if the air pressure sensor is operating correctly.
8. Check the PCB DIP switch settings.
9. Adjust the offset pressure.
10. Check that the gas orifice used is for the correct gas type.
11. Check the flue and air intake for accumulated water (for vertical flue installations).
12. Tighten the ground connection screws on the heat exchanger.
13. If the error conditions remain after checking these items, replace the PCB.
No
Is the igniter voltage
correct?
Yes
Is the igniter
electrode clean?
Is the igniter electrode
damaged?
Yes
Replace igniter assembly
Description
No
Check the connections
Test the voltage between #2 and #4 at
CONW1. Ensure that it is the same as the
supply voltage (AC 230 V).
No
Clean or replace the igniter
electrode