Navien NHB-055 Service Manual page 94

Fault
Flame loss and noise
occurs after ignition
94 NHB Service Manual
Possible Causes
Digital pressure
Check the offset values for Min fire
Model
NHB-055
NHB-080
NHB-110
NHB-150
Replace the electrode or clean the fire detecting electrode.
- Cause: Due to the properties of the electrode, the oxide film is created due to
- Check-up: Use sandpaper to clean the fire detecting electrode covered with
Flame Rod
(Electrode)
Check the tightness of the screw or ground bolt in the Chamber + SC heat
exchanger.
- Cause: Screw or ground bolt in the chamber and SC heat exchanger can be
Tightness of Screw or
Ground Bolt
- Check-up: A failure in the current flow between the chamber and burner may
Check method
manometer
Gas Type MAX fire % CO
NG 8.9
LP 10.2
NG 8.9
LP 10.2
NG 8.9
LP 10.2
NG 8.9
LP 10.2
CO value
2
long-term exposure to the high temperature; therefore, errors may be caused
in detecting the fires.
oxide film or replace it.
loosened by the vibration or external impact when operating the boiler (water
heater).
cause the flame-out; therefore, the tightness (fastened) of the screw needs to
be checked. [Fasten the ground screw (2EA) after fastening the assembly screw
(3EA) in the front of the heat exchanger]
Model Gas Type
NG -0.04 in ± 0.01 in
NHB-055
LP -0.03 in ± 0.01 in
NG -0.04 in ± 0.01 in
NHB-080
LP -0.02 in ± 0.01 in
NG -0.04 in ± 0.01 in
NHB-110
LP -0.02 in ± 0.01 in
NG -0.04 in ± 0.01 in
NHB-150
LP -0.02 in ± 0.01 in
Offset value for Min fire
Min fire % CO
2 2
9.5
10.8
9.5
10.8
9.5
10.8
9.5
10.8
Offset
Version 1.0