Navien NCB-180 Service Manual page 92

Fault Possible Causes
Flame loss and
noise occurs after
ignition
Flame loss during Blockage in the
2nd stage gas orifice plate.
PCB DIP switch
setting error
Other trouble
Defective PCB
Digital pressure
manometer
Check the offset values for low fire
Flame loss will occur if the gas orifices are clogged.
Remove the gas inlet pipe and check for debris; remove and clean the orifice

plate if necessary.
Check the PCB DIP switch settings.(Refer to page 19)
* Check the flame detection AD
value for proper resistance.
(refer to page 42~43)
If the issue continues despite checking above items, replace the PCB.
Check method
Model Gas Type
NG
NCB-180
LP
NG
NCB-210
LP
NG
NCB-240
LP
Offset value for low fire
Offset
-0.04"±0.01"
-0.03"±0.01"
-0.04"±0.01"
-0.02"±0.01"
-0.04"±0.01"
-0.02"±0.01"