04Error - Navien NP-180 Service Manual

5.2. 04Error

Error occurrence conditions and check items.
Error
1. Pre ignition false-flame
If a flame signal is detected continuously for 6 seconds before combustion
(stand-by, pre-purge, pre-ignition), a false-flame error 04E (automatically cleared)
is dis-played on the thermostat, and the system performs continuous post-purge
04E
and operates the pump.
False-flame
2. Post purge false-flame
detection
If a flame signal is detected continuously for 6 seconds when the system performs
post-purge as fuel supply is stopped, a false-flame error 04E (automatically cleared)
is displayed on the thermostat, and the system performs continuous post-purge
and operates the pump.
1. Check if gas leaks due to defective air sealing of the main gas valve.
2. Check if electricity is discharged from the electrode.
Check items
3. Check if gas is supplied at higher pressure than the standard gas pressure.
4. Defective PCB.
Is the flame detected
during no burner
openrarion?
Replace PCB
©Navien America Inc. 2010
Description
No
Yes
75
NR/NP series service Manual
Clean or replace flame rod
Check the current of CN 19: 7-20μA
Check the voltage between two wires
of CN 19: 10-20VDC
Version 2.0