Navien NP-180 Service Manual page 78

Check method
Error type
Flame before/ Leakage from
after combustion main gas valve
Discharge of
electricity from
electrode
Error before
after combustion
main gas valve
Other trouble
Defective PCB
©Navien America Inc. 2010
Cause
Replace the gas block if flame occurs before combustion or if there is
remaining flame after combustion is stopped.
Spark discharges from electrode to flame sensor at ignition.
Replace or correct location of flame detecting rod.
Gas may leak as the main gas valve is pushed by the gas supply over
the standard pressure.
Check the supply pressure: NG: 5"(6" 180 model )~10.5" WC,
LP: 8"(9" 180 model) ~13.5" W.C
If the gas pressure is too high, transfer the problem to the gas
supplier, and replace the main gas valve.
If gas leaks, close the main gas valve and repair the unit before usin
the system.
If the trouble continues despite the checking of above items,
replace the PCB.
NR/NP series service Manual
Check method
76
Version 2.0