Error - Navien NCB-24LSWE Service Manual

5.2.3 Error 004

Error Conditions and Checklist
Error
1. Pre ignition false-flame
2. If a flame signal is detected continuously for 3 sec before combustion (stand-by, pre-purge, pre-
E004
False-flame
3. Post purge false-flame
detection
4. If a flame signal is detected continuously for 3 sec when the system performs post-purge after the
1. Check for gas leaks and defective seals on the main gas valve.
2. Check if a spark of sufficient intensity is discharged by the electrode.
Checklist
3. Check if gas is supplied within the correct pressure range.
4. Check the PCB and replace if faulty.
Testing method
Error
Flame
Main gas valve
before/after
combustion
Electrode level of
discharge
Error
before/after
combustion
Gas valve
Other faults PCB fault
90 NCB Service Manual
ignition), a false-flame error 004E (automatically cleared) is displayed on the front panel. The system
performs a continuous post-purge and starts the circulation pump.
gas supply closes, a false-flame error 004E (automatically cleared) is displayed on the front panel. The
system performs a continuous post-purge and starts the circulation pump.
Cause
If flame occurs before ignition or if gas continues to burn after combustion stops,
replace the flame rod.
leak
Spark discharges from electrode to flame sensor at ignition.
 Replace or correct the position of the flame rod.
Gas may leak from the main gas valve if the gas supply pressure exceeds the boiler
specifications.
 Check the supply pressure: NG: 17 - 25 mbar, LP: 25 – 35 mbar
 If gas pressure is too high, notify the gas supplier and if necessary, replace the gas
valve.
 If there is a gas leak, close the gas supply valve and repair the unit before using the
system.
If the error condition continues after checking these items, replace the PCB.
Description
Testing method
Version 1.0